Your play in the opening seems quite sensible, but most players prefer 6.Nc3 to 6.Nf3, there's no need to give Black the chance to pin your Knight with 6...Bg4. Still, 6.Nf3 is a developing move, so it can't be bad.

I would prefer 12.Bf4. It seems to me that e5 might be an important freeing move for Black, so I would like to clamp down on the e5 square, Besides, it just seems like a more active diagonal. The Bishop on e3 has a purely defensive function, like a tall pawn.

I'm not so sure about 18.cxb6. After 18.Nc3 Nxb4 19.Nxb5! axb5 20.Qxb4 I think you end up with a nice protected passed pawn on c5 and a small, but clear advantage, 18.cxb6  you get duelling Knight outposts, and I think his is just as good as yours--and he gets to target your b-pawn. And he made a mistake when he traded his great Nc4 for your slightly bad Be3.

You're kicking yourself for nothing on move 25. After 25.Nd7 Qd8, Black is OK.  27.Bxa5 was probably a little bit better, but the game is pretty even in either case.

I don't think your switch to the kingside was too good. Black could have played 28...e5 to liberate his position and make his Bishop strong.

Your opponent kind of fell apart at the end, which is too bad because the position was interesting. I think you were a little sloppy towards the end yourself: I think 34.b6! was quite a bit better, and 35.Nxc3 Qxc3 36.b6 was also better

I think you pklayed quite well, The only serious tactical mistakes you made came after your opponent had alreadty blundered himself. There were some difficul decisions in the game, and I think you handled them OK. 

Thank you for your very detailed analysis.  That 18. Nc3 line is very interesting, I need to work on seeing those types of tactics.

GG, think yur R play in mid-game was a bit sluggardly, i.e. moving the R f-file instead of Ra out of B pin. Rf got back home eventually...