But what are people's strengths if they suck at chess?

So upon some observations of analysis of previous games I've played, here are 3 distinct mistakes/blunders I've been making as it seems:

1) I spend too much time aiming for the top left hand side of the board when I'm black (f2 square) and not enough pressure coming from corner coming from the queen side?

Same applies when playing white - too much time aiming for f7 square and not enough pressure starting from the bottom left queen side around the d file?

2) I should not be affraid to "waste" time readjusting key pieces back towards the starting points should my opponent notice my tactics and start putting counter pressure on my own pressure settings if such pieces become decreasingly safe? Maybe not every move doesn't necessarily have to be an of ego?

3) castling and/or connecting rooms is important however sometimes I castle assuming it will make my position safer without realising the a and h files for the king can be as deadly as f7 and F2 spots? There might just be better moved to make besides castling too soon and hold it back a little once I've noticed other opportunities first?

Well if you want to get better, short time controls are not good for that. Even those 10 minute games are too short let alone pure blitz. Speed chess will not get you better in most cases.

To play good chess you do not have to be incredibly smart, neither will every smart person play good chess. 

10 minutes is not enough if you wish to be better. If you just want to casually play, it is ok. If you play 10 minutes games, you do not have the time to really think in a critical position or calculate something. Strong players can do some calculations really fast, but we weaker amateurs just can't and will blunder in those time scrambles. And if we blunder all the time and do not find the best moves we can, we will not progress. At 1 500, I might get away with playing 15 minutes with increment, but I would surely play worse than I do with long time controls. It is better to play lesser number of games but more quality ones than several shorter games per day.

Thanks for your responses here fellas! Ok, speed games aren't the thing for me for the time being and from what I am gathering to get better at my chess has really nothing to do with being brainy - it's all about putting in lots of effort??

Yes, a lot of effort and to know what you are doing. If I may, I will give you some tips. This is what I did to get from 800 to 1 500 (although I was probably around 1 000 realistically when I started this year in February, as I did play the game long time ago, when I was a kid:

https://www.chess.com/blog/nklristic/the-beginners-tale-first-steps-to-chess-improvement

I hope it will be useful to you.

10 min is not enough because 15 sec per move is a joke unless you are already very stong at slower speed like 15+10

No credible professional coach will advise you to play 10 min games if you are serious at improving your understanding of the game!

In fact it's a requirement from any good coach to any beginner to play and to think carefully on EACH move.

You are overthinking this too much. This is going to sound a bit harsh, and I apologize for that, but here is what is costing you.

You do not pay attention when you make moves. As a result, you give away pieces for free and make trades that do not make sense, because you didn't look at the board long enough. The time control you are playing does not help.

Here are some examples of this. This will probably be the roughest part of the post to do through, but look at these games. I'm not looking for anything fancy, just simple mistakes like "don't give away your pieces for free" or "don't trade your better pieces for their weaker ones" kind of stuff.  

https://www.chess.com/live/game/5745018633 

Move 8, you move your pawn out of the way of their bishop to take your knight for free with check, which they'd probably then take the rook with as well. You guys exchange and they don't even notice this free piece. They move a pawn move 10, you take it, and now they can just take your rook for free. This time they catch it.

Move 15, your knight is protected by your queen, but you move it out of the way so they can just take your queen. For what? Your knight did attack their rook, but a rook is worth less than a queen. 

Move 19, you attack their knight, except all that happens is you just gave them a fork on your king and rook. A knight for rook trade is not good for you, rooks are usually worth more than knights. You then undefend your rook so that instead of a knight for rook trade, they take your rook for free.

This wasn't because of set-up by your opponent either. They are also making a ton of mistakes and handing you freebies. For instance they handed you their queen for free on move 13, which you took, but you lost because you gave away more pieces than they did.

https://www.chess.com/live/game/5745082541 You gave away your rook for 1 pawn on move 11. On move 20 you decided to trade your queen for a rook. Rooks are worth less than queens. On move 25 you can just take his knight for free, but instead move your bishop for no reason and let their knight attack your rook. 

https://www.chess.com/live/game/5744518498 Move 6 you give them a pawn for free, they have more defense than you. Next move you decide to upgrade it to a free knight instead before backing off. Move 13, they are attacking your queen, but you let them take it.

https://www.chess.com/live/game/5744505988 Move 13 you gave them a pawn for free. Move 14 you let them take your rook for just a bishop. Move 18 they are attacking your queen with an undefended bishop. They sneak it behind a pawn attack on your bishop, but by avoiding that you just let them take your queen for free, rather than taking their bishop as a defensive move. Move 20 you just give them your rook by putting it on a square they can take it for free and check you.

Strategic failures are the least of your concerns. If they can take pieces for free they don't even need a plan, they can just keep making aimless moves that don't blunder things until you give them something to take until they have enough of a lead to win. They just have to do enough to give you chances to help them. 

For the record, this isn't unique to you. This is an extremely common mistake in chess at that rating range. Probably the most common. 

To fix this, you need to slow down and look at the board. Are they going to take a piece for free next move? Move it out of the way, or protect it. Don't exchange your better pieces for their worse ones. For example, trading a queen for a rook is not good. So avoid doing that.

To successfully slow down enough to do this, you'll probably need more time and should play faster controls.

I have been playing chess since I was 6 (I am 16 now). I believe that the best way to get better in chess, or anything in life, is through practice. I didn't even win a single game for two years after I started playing. Patience is key, practice often, and think about all the possibilities a move can give you before you make it.

They get mercy and the opponent resigns.

hi

It has to do with both.  Like anything that anybody is serious about, it takes a lot of effort to get good.  However, being smart allows you to understand things better, so you can progress faster, and in principle you should top out higher.  However, starting as a young child also helps since you can fill your brain up with important chess knowledge rather than useless things like how to get into and graduate from college and have a productive career.

At a rating of 685, there are two easy things you may benefit from:

1.  Pick up an end game book and learn the basic mating techniques with king and queen versus king, or king and rook versus king.

2.  Learn the first few moves of important opening lines - one opening move with white and the major defenses, and one major defense for each of the major white opening moves.

That will get you close to 1000.  To get over 1000, you'll probably need to play at least a little almost every day, preferably at 15/10 or longer time controls, so you start to see and avoid blunders.  The higher you want to go, the more time you'll have to spend to stay in practice.

I agree with all the points the OP made. But I also have to agree to @quakquak2

Your biggest problem is you are not considering what your opponent can do. You don't seem to have much problem capturing your opponents pieces, but you frequently leave your own pieces hanging. Spend more time thinking about what your opponent can do and less time thinking about what you can do. Also never resign. 

Well what do you think I am doing that's making me leave pieces hanging? Wtf should I so instead?

     Here's another vote for playing longer time controls. When you play more slowly you can look at the potential moves of all your pieces and all your opponent's pieces everywhere on the board. And if you're going to spend an hour or two on a single game you're apt to take it more seriously rather than pausing only briefly to pop open another beer. 

     It can be fun to play speed chess with friends while drinking and having an all-around good time, but it's even more fun if you can play competently and win more often. The way to do that is to raise the overall level of your game. Play some more serious longer games, analyze them afterwards, get a chess book or two (plenty of good recommendations in some "For Beginners" forums here) and take the time to really absorb what they have to say. Chess is hard to master and it takes work to become a decent player, but many people all around the world have gotten a lot of enjoyment from the game for centuries.

     Not every GM understood the game seemingly instantly as tales of Capalanca or Reshevsky might indicate. Magnus Carlsen, with his high intelligence and phenomenal memory, reportedly spent many hours in his childhood studying chess in order to be able to beat his older sisters and played in FIDE tournaments at a young age but had an unremarkable rating of 904 (age 10) when he got a good coach and suddenly took off on his rapid rise to the top.

Thanks for sharing