I think you should avoid risky sacrifices in the opening until you're a great tactician. for example, in our last game which we couldn't continue due to technical problems,
[Event "unratedin rovansi"]
[Site "?"]
[Date "2007.06.24"]
[Round "?"]
[White "ben 2"]
[Black "ih8sens 2"]
[Result "*"]
[ECO "C63"]
[BlackElo "1566"]
[PlyCount "25"]
[EventDate "2007.04.22"]
[SourceDate "2007.04.22"]
1. e4 e5 2. Nf3 Nc6 3. Bb5 f5 4. Nc3 Nf6 5. exf5 e4 6. Nh4 d5 7. d3 Bb4 8. O-O Bxc3 9. bxc3 O-O 10. g4 Ne8 11. Bxc6 bxc6 12. Ng2 Nd6
, eventhough you said my knight was weak an those pawns would get me in trouble, white stands a lot better here, due to kingside attack. and actaully, 10...Ba3! instead of g4, as suggested by rybka, almost gets black a won position, being a clear pawn up.