Which Variations of The Sicilian Are Best?

The Sicilian has so many variations which one should players spend time studying?

 (1) Judging by your games, you shouldn't be thinking much about openings - instead, you should practice tactics more, and also just play a lot of chess games with the goal to not hang your pieces or lose to basic tactical ideas. This is what will determine how well you play, until you are much much stronger.

(2) If you insist, I would recommend the Sicilian Kan. The vast majority of open Sicilians are NOT for beginners, and some are not even good for intermediate players, and only for masters. The Sicilian Kan is good for beginners because black generally doesn't have to worry about early attacks by white in the opening. 

You can play any opening you want as long as you stick with it. I've played the Sicilian since I was below 1000. Don't focus on specific variations because at your current level you won't see them often. When first starting out I played c5 because I wanted to capture a central pawn with a flank pawn and have better central control. Beyond that I just tried to get similar positions each game and watch for tactics. I lost a lot in the beginning in sharp positions but it made me better in the long run. Eventually you get sick of hanging material every game and start paying more attention lol.

Some openings, like the Najdorf Sicilian, are defined by theory - they have no real "general ideas", just a set of computer lines that somehow work out. The OP should definitely not learn these openings. He should avoid all openings defined by theory.

Possibly helpful:

Starting Out: The Sicilian by GM John Emms (2009)

https://web.archive.org/web/20140627122350/http://www.chesscafe.com/text/hansen123.pdf

The February 2017 issue of Chess lists the top twenty openings compiled from a list of 4561 December games where both players were rated over 2400 Elo. One can not take position on this list too seriously because it is greatly influenced by how the openings are grouped. For example, all the Retis are grouped together, while English is separated into 1...c5, 1...e5, etc. Nevertheless, for what it is worth, some of the list entries are: 336 Retis, 198 King's Indians, 186 Caro-Kanns, 159 declined Queen's Gambits, 158 Nimzo-Indians, 148 Najdorf Sicilians, 135 Slavs, 128 1...c5 Englishes, 114 Kan Sicilians, 102 Italians, 98 1...Nf6 Englishes, 97 Queen's Indians, 88 1...e5 Englishes, and 78 Berlin Ruy Lopezes

"... anyone who is just starting out should not dive into the vast ocean of theory that is the Najdorf. For beginners, the time invested in studying even minor lines can be more productively used solving tactical puzzles and basic endgame technique.
...
... In some lines, a good understanding of basic principles will take you far, while in others, such as the Poisoned Pawn (6 Bg5 e6 7 f4 Qb6!?), memorization is a must, as one wrong move can cost you the game in the blink of an eye. ..." - FM Carsten Hansen (2006)
https://web.archive.org/web/20140626175558/http://www.chesscafe.com/text/hansen87.pdf

Honest perspective:

When I was 1000-1400, I played the Caro-Kann. Had good results, gained those points in less than a year.

When I was 1400-1800, I played 1...e5. Had good results, and gained those 400 points in less than a year as well.

When I got to 1800, I thought, hey, why don't I start playing "grown-up openings" now that I'm a decent (as I thought at the time) player. So I started playing the Sicilian. I never played the Najdorf, but I played the Accelerated Dragon, Kan, and Taimanov. 

I stayed 1800 for two years despite playing 200 tournament games. For a while I also played the French, which I had probably better results with than the Sicilian, but not noticeably.

At some point last year I went back to 1...e5 and now I'm 1932

I am a believer that most openings that get out your pieces and make sense should work (although to be fair, 1...c5 doesn't really prepare to get out any of your pieces, so in a way it breaks this principle). I never criticize a player's opening choice, especially if that's what he has prepared or plays in tournaments. But I'd just like to say that if you have a determination to play some variation of Sicilian as black, it may be worth it to look into other openings.

As a novice who currently plays the Taimanov (similar to the Kan), I reckon you have to understand the principles behind the Kan if you don't want to get unexpectedly destroyed:

• Hang on to your dark squared bishop like crazy until the endgame. Since your dark squares are weak, you've got to defend them with that bishop. Don't ever give it up if you can't at least win the exchange, and even then, you should pay extremely close attention to your now extremely weak dark squares.
• Organize for a ...d5 pawn break. This usually breaks up White's center, diluting the power of his kingside attack (as usually, active center piece play > flank play) and also gives you counterplay in the center.
• Go for a queenside minority attack. This involves rushing your pawns down the queenside to try create weaknesses (e.g doubled pawns)/chase the knight at c3 (to try win the e5 pawn) and putting rooks/queens on the c-file to try get a rook/queen on the 2nd rank.
• Try to exchange off one of your knights for your opponent's dark squared bishop. If you can accomplish this, quite a lot of load is taken off your weak dark squares.

For a novice even more new to chess than me, I would recommend the Dragon if you insist on a Sicilian:

The reason why I recommend this opening is because it's tactical (which is what many think novices should work on first). Sure, the Yugoslav Attack is surprisingly devastating against it, but I doubt there are many on my level who can win as White solely because of the Yugoslav.