How to continue from here?

I played this game against my self in my house to train. I reached this position, and i just had no idea how to improve my position, as black or white. I don't know what i will do if it will happen in a real game for example.

can you help me to find a way to improve the position for both sides?

c4 and b2 are targets.  black playing a4 might isolate both and let you build up attacks on each.

well, that's pretty much close the position, and how to continue from there? black doesn't want to ruin the beautiful stracture there, and how to continue from there, for white and black?

There is a forcing and critical line both sides needs to calculate, e5 Be3 Qxe4, which nets black a pawn. White needs to find compensation in that line. Also g5 Be3 Qxe4 is possible and should be looked at. As black, I would go into that line with a pawn up advantage. White needs to figure out how to either recoup the lost pawn or create compensation by increased piece activity, an attack n the king, or something. That is were I would head from that position.

Nb7, putting pressure on the c4 pawn. After Ba6, this pawn cannot be defended.

Really? b3, Bf1, Rc1 won't help defend that pawn?

Bf1 is the only move that could defend it. If Rc1, then you take the pawn anyway, he has to recapture with his Q first, lol. If b3, after Nb7, you push the a pawn. Also if Rc1, you win the e pawn. Bf1 is the only good response, and it takes white's bishop more out of the game and tethers it to the defense of that pawn.

Your line works too.