Pushing the central pawn

I've recently started playing e4 as white and find myself holding the central pawn whilst defending it against the opponent. Last night I played a game and came out with a good advantage at the opponent but chose the wrong moment to push the d4 pawn (even though it was supported by e4 and c4) and the opponent could have taken advantage of it.

I've seen games where ending up with an isolate pawn on d5/d6 is good (in this case there would have been an exchange leaving my past pawn isolated on d5 and I've seen it bad so how do I chose when to push? I don't want to end up getting advantages in my openings only to give it away in the middle game!

Thanks!

How exactly is d4 supported by e4 and c4?

I believe he was talking about "push(ing) the d4 pawn" to d5, where it would be supported by c4 and e4.

Thank you Bur_Oak, yes I meant that pushing the d4 to d5 is supported by c4 and e4. It was the centre-counter my opponent played against me, FallingUp, a weak opening that I managed to take advantage of with pawns on c4 and d4. My pieces gradually developed to better squares (whilst he continuously remained defensive) and I had a distinct advantage (according to Fritz) of approximately 0.8. But then I pushed at the wrong moment grrrr. I can see how he became more activated aftwards so it was a mistake, but at the time I felt it was my only moment to do it and to not end up just defending my central pawns whilst he attacked them (not that he did!). Maybe I should have worried less about pushing it and concentrated on building up a kingside attack with the extra space I had?

I agree FallingUp, I had built up my centre pieces but then I get to this point where I'm thinking, and what now? Grand Prix Attack's and Kingside attack I can see how white/black immediately goes for the attck but when it comes to a central game I guess I find it difficult how to utilise the space quickly i n order to bring my developed pieces around to the kingside. Do I leave my knight on c3 to hold the centre pawn or bring it round e2-g3 to aid the attack. Is my knight on f3 better placed holding the centre or do I use an outpost on e5 to aim at the king. If I don't get the balance right then black's counter attack on my centre breaks through and the game swings towards him whilst if I just sit there holding the centre I'm not doing anything! Perhaps I'm just concentrating too much on the centre and should focus more on the attack.