I leave you with IM Silman's instructive analysis:
Black appears to have an excellent position. His bishop is active and his pawns on e6 and d6 cover the key squares e5, d5, and c5. To make matters worse for white black possesses more space on the queenside.
White center pawns are pointing to the Queenside and his bishop also aims in that direction. This suggests white should look for queenside play.
Neither player has any aggressively posted pieces on the kingside. There are also no weaknesses on either side to attack, this tells us that kingside attacks shouldnt be considered for either side.
Both sides have solid central positions so active play there is doubtful.
White's bishop, which happens to be a 'Good Bishop' since his central pawns are on the opposite color and thus dont block it, is less active than blacks counterpart.
What can be done to activate whites bishop?
Neither side has any clear weaknesses to attack. This is the key idea in the position! How can white create targets in the enemy camp?
White should be asking himself the following questions 1) How can I make my bishop stronger? 2) How can I get both of my rooks in the game? 3) How can I initiate queenside play? 4) How can I create weakness in blacks queenside fortess? 5) How can i get my knights into the action?
Answer: 1. a4!
The only correct decision. Suddenly White is challenging Black for queenside space. He is hitting the black b-pawn and by doing so, turns his bishop into an active piece. Also the rook on a1, which seemed so useless a moment ago, shows that it is beautifully placed on its original square.
Black doesnt like 1...bxa4 since 2. Rxa4 lets white build-up strong pressure on the new target on a6 (white will double rooks on the a-file when both rooks and bishop will take part in the assault against a6). If 1...Qb6, then 2. axb5, axb5 3. Qb3 shows b5 to be a target.
This strong move does several things: 1) takes the b6 square away from blacks pieces; 2) stops the black a-pawn from giving support to b4; 3) it fixes the a6 pawn as a target (the best targets are thise that cant move); 4) it fixes the a6 pawn on a light colored square making the white bishop a very proud piece.
The concept of fixing targets on attackable squares is very, very important.
After 2 a5! black position is very uncomfortable. Amazing isnt it. 2 moves ago black appeared to be doing well, and now with the proper evaluation and plan by White, the picture has changed drastically.