Ahead in game, but just cant find a way

Got early lead in this game, but I was spending much more time on moves than him. This is 15+10 game. Very closed game for me, I tried to find an entry to his defence, but in the end I lost my advantage and rest is history.

When I am leading with 2 points like I was, should I be happy to make fair trades? Or even try to force my trades, when possible?

Fair trades are a good idea, but you cant get too crazy with it and still need to play well.  These days computers are beating super grandmasters with pawn odds, exchange odds and the like.  Being ahead material doesnt mean that you can just be mechanical about it.  You can still get outplayed.  

Absolutely - and with that in mind, I'd have chosen 28 Qg4 to get the Queens off