Analysis of a middlegame out of the Queen's Pawn Game: Zukertort Variation What positional considerations must be made in order to come up with a plan for White in this position?
What are the ideas behind the central squares and weaknesses that must be analyzed for both sides?


Position:

 r2q1rk1/1b1nbppp/pp2pn2/2p5/2PP4/2NBBN1P/PP3PP1/R2Q1RK1 w - - 3 12
The position is basically still quite equal, although black has a tiny bit less space to maneuver, so the first order of the day is to develop the Qd1, and bring the rooks to the center. The position is still VERY fluid in the center, so it is impossible to say about one plan that "this is THE plan". Also, a fluid center makes it very hard to develop a kingside attack, even though you have some pieces that are aimed that way.

After developing the queen and rooks, you should either look to double rooks on the d-file, or you may try to expand on the queenside with a3, and b4...if possible. This is hard right now because it may leave c4 very weak, which is why in the main line below, I played b3 instead. You need to watch out for b5 in any similar opening because the Nc3 now hangs.

Another idea is to try to occupy the outpost on e5 with a piece. That is impossible now, but depending on how black plays, it might be possible. That plan is not going to be 100% effective because black can always play c5xd4, reducing white's influence on e5. 

Other than development, your main plan is mostly prophylaxis. Black is trying to trade down some to gain breathing room, so you want to play moves that make that tougher to trade pieces, or at least trade fewer pieces. With the potential for open files on the d-file, and e-file (if you played d5, which is another move both sides need to consider on every move for now), it is likely that at least one set of rooks will come off the board. You do not want to trade because you have more good squares for your pieces, and thus, more room to maneuver.

Here is a sample line that white was successful in finishing development, and limiting trades...for now. Now that d5 is no longer possible, black will reposition the Re8 and try to trade material down the d-file. It is still equal per the computer. There are many more lines, and possibilities at this early stage, but hopefully, I have given you enough ideas on how to adapt to any other changes black's play throws at you.

In the end, I suspect that if you have any advantage, it may be a slight endgame advantage where you get one rook on the open d-file, and maybe a minor piece each left...the file being the major plus, along with b6/a6 being targets. 

 [FEN "r2q1rk1/1b1nbppp/pp2pn2/2p5/2PP4/2NBBN1P/PP3PP1/R2Q1RK1 w - - 0 1"]

 1. Qe2 Qc7 2. Rad1 Rac8 (2... Rfd8 {Getting ready to immediately liquidate the center is also possible.} 3. d5 $6 exd5 4. cxd5 b5 $15) 3. Rfe1 Rfe8 {This anticipates d5 prophylactically.} (3... Rfd8 4. d5 exd5 5. Nxd5 Bxd5 $1 6. cxd5 b5 $11) 4. b3 (4. dxc5 $6 Nxc5 5. Bc2 Ncd7 $1 6. Nd2 (6. b3 b5 $1 $17) 6... Ne5 7. Na4 b5 8. Nb6) 4... cxd4 (4... b5 $6 5. cxb5 cxd4 6. Bxd4 $16) 5. Bxd4 h6 {But with some play for both sides}