Another newbie

I have been writing PHP for almost a year now and someone on phpfreaks told me the other day that my code was very sloppy. Since I want to more more into programming than design, can anyone recommend where to learn how to make sure your code is clean, optimized and as error-free as it can get? Even if it is the style of how to write the code, please let me know....I know noone can be the perfect programmer, but I would at least like to be a decent programmer :) Jay