It's been a few days since you asked. I wonder if your game has moved on...
You start off with a king pawn opening and your opponent replies with a Sicilian Defence. In Sicilians, white classically attacks on the king's side and black counters on the queen's side. Your first two moves each are fairly standard. Your third move d3 is unusual though. Why? Because it's quiet. There is no d4 cd, blasting open the center. Sicilians are usually quite 'sharp', meaning they need a lot of involved and often deep accurate analysis of tactical attacks and defences. There are quiet Sicilians; they're usually called 'closed' Sicilians and often involve white playing Nc3 and Bg2 as well as d3 though not in conjunction with Bg5. Closed Sicilians may be more strategic but often they are just a slower build up to an attack. In fact they often turn into something called the King's Indian Attack (KIA).
At the moment you have neither of these overall patterns. Black currently has a 'hole' at d5 that you may be able to take advantage of, especially if you can fix the c and e pawns and exchange off his white-squared bishop. But in modern Sicilians, black often has a hole there and looks to compensate by counterattacking. At the moment it seems you're perhaps offering to exchange black squared bishops perhaps, though not sure why. That Bg5 is not really helping you short or long term.
So let's think generally. Where would be good places to put your pieces if you maintain the closed pawn structure? g3 and Bg2 would be normal in a KIA (and in this case would keep an eye on the hole at d5) followed by 0-0. (The B on g5 is misplaced because black can either exchange it off, force it to retreat, or delay things waiting for your Bg2 and then drive it back with pawns and get a king's side attack of his own going.) The queen's knight might go first to d2. Medium term, you will have to choose your strategy: will you attempt to attack in the center or will you immobilize it and then attack on a flank? KIA often looks to a white f4 (maybe not in this case) or a queen's side pawn expansion.
Lots of generalities, I know. But I used to find these were sometimes useful in setting the overall context before getting into detail... those details, of course, which a computer can do for you nowadays anyway.
