Frustrating...

This has been typical of my games of late.  I get into a good position and then I spend a long time looking for a move, checking threats, and then end up blundering.  I don't get what is going on.

If it's because of tactics then you should work on tactics.

First step would be playing game to mate or get mated and looking for tactics to the last breath.

Well, I will say that I do lose games due to tactics, as does any one.  I'm not sure that a tactical weakness has been the cause recently.  For example, in this position I kept telling myself that I can't give up control of e3 because of the knight fork.  Instead of playing something reasonable, I suddenly play the one move I tell myself not to make.  I was thinking about f4 after moving the queen because I wanted to take away the square from the knight.  Its like I keep losing track of where I am at the board.  Basically, I keep skipping steps.  

White's position seems so nice before 27. f4, too...

I always check where the knights can go before every move.  I also check every check etc.  Its just part of my routine before I move.    

Sorry, Qb1 is better for white than f4 even if black could not Ne3+.

But i think i know what is going on. People lose threads in their heads when they feel, they played better and they obviously winning. (Me too some time ago.) Work it out. It's not win if you did not win. You are no better, if you can not win.

Take care.

After 3...b6 a better move for White is 4.c4 setting up the Maroczy bind. Look it up on line.