I always lose online?


I just played through two of your games. It is probably best to play much longer time controls first, and really consider your moves. Chess takes a lot of time to begin to understand. It takes years and years of playing. Good luck

Well, there are a lot of experienced players here, as in people who play 5 days a week for years, so (and I'm assuming you're relatively new to the game) it's not that you're not playing smart, it's just these guys are the next step up from whoever you're playing face to face with.
The important thing to do is play often and work on fundamentals like making sure you know what your opponent's last move threatened before thinking about what you want to do. Making sure your intended move doesn't leave something important undefended. It's daunting to be aware of the whole board all the time, but it's encouraging that the position only changes one move at a time :) Pay attention to how each move changes the position.
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That said I'll go over some opening basics I saw you miss in some games :)
The opening is all about getting your army into the game... as a team! If you move each guy twice in the first 8 moves while your opponent brings out 8 separate guys you'll be outnumbered 2 to 1. This is called development. Pawn moves do not count as development. Develop your bishops and knights first, castle, and develop your queen only a few squares away from her home square (she's so important that any piece can force her back in the opening so she's not yet safe to go attacking).
Pawn moves are very important though, even though you'll only spend a few moves on them in the opening. Pawns stake out space your army uses to maneuver. Because the most useful space is central space (your pieces can use central space to go to any part of the board) it's always a good idea to claim central space by moving either your king's or queen's pawn two squares forward in the opening. Don't give up your central pawn(s) position unless you feel like you're forced to.
Lastly castling is important for two reasons. It gets your king to safety behind a wall of pawns (pawns that haven't moved yet are the best defenders) and brings your rook out of the corner.
Hey mate, If you are new then try free chess course. I learnt how to play the game there and it helped me raise my rating by 150 points
http://www.chesskids.com/kidzone/index1.shtml