I've been programming games for a long time now.Started doing tic tac toe, breakout,pong etc..when I was in school.Now,till date the most advanced game I've made is a 8-ball pool game made with the physics engine Box2dFlashAS3 and a platform game with levels. When I did platform games, I've always wished if "I knew" how to make an engine, so that I could re-use it. When I see games that have slopes  , curved slopes, perfect gravity and real-life physics, I've always wished I knew how to "code" the engine. Please suggest me techniques and also include links and articles to whatever relevant knowledge-base is necessary. Well,when replying, please write down the answers point-wise.

The most advanced games I've made are a 8-ball pool game made with the physics engine Box2dFlashAS3 and a platform game with levels.

When I did platform games, I've always wished to know how to make an engine, so that I could re-use it. When I see games that have slopes, curved slopes, perfect gravity and real-life physics, I've always wished I knew how to code the engine.

Please suggest techniques and articles for whatever relevant knowledge-base is necessary.