Hi guys, I am now a uni student, but I used to be my A-Level Chess Club president. Back in secondary school, I used to represent my school 3 years in a row for competitions. I am a bit rusty now, but i can still give pointers in chess.
The keys to success in chess are practice and memorising positions. Great chess players like Grandmasters use mainly pattern recognition in playing chess, and little strategy analysis. Hence, it would be good to buy books with good openings, endgames, etc and memorise positions. If practice is your thing, play against softwares like Chessmaster 9000, or join a chess club and play against good players. It doesn't matter if you keep losing, because 'no pain, no gain'. One good thing about practice games is that you also improve your pattern recognition skills when you recognise the positions that occur frequently on the board, and you can learn from your mistakes or from the great moves of other players who are better than you are.
K, that's all from me. Hope this helped. Also try chess puzzles. Lots of them.