Game evaluation help

One of my chess difficulties is converting an advantage gained in the opening into a win. In the following game, I had a two pawn advantage, yet I lost. Can someone help me identify and correct my errors?  The time control was G/60. Thanks.

You played really well you just lost the control at then end, in chess you need to keep finding those good moves that keeps your advantage or hold your position, one bad move can cost you the entire game. First of all you need to find those critical moments where you could have played better, like at move 23 b×c4 would be better as then you would have only one pawn island and at move no 35 you need should have defended your second rank with Ra2 and your opponent would not get that much counterplay. 

I'm not a strong player to correctly point where you went wrong that was just my point of view which can be wrong of course 

Thanks for your reply. On move 24 I chose Rxc4 rather than bxc4 because I wanted to trade down to the endgame. I did consider the pawn chain, but I think trading down may have been an error in judgement.

Nice game Red Dalek!
Well played opening. Later, that Knight at d5 (pinned) looks little bit risky but you handled that!

24. R:c4 was correct, according to the principle - you are up, you need to trade pieces down.

But in the end you made two big mistakes
1) You opened your king - very risky in positions with major pieces - Kings safety first!
2) Nd2 was a blunder, but probably at this point black's position was very good

I think that the most important conclusion is that you should remember about your kings safety! Do not move pawns from your king.

thx

Mat, thank you for your timely response and helpful comments. I will incorporate them into my game.