EDIT: ok, I'm gonna try and learn more about GL and about engines and all the stuff needed in an engine

Hi, I know java code, and quiet well (the basic stuff), now I'm making a really simple game in Slick2D, and I want to make my own engine, for the next game, my questions are:
1)What do I need to know in LWJGL to make a basic engine, and how do I progress from there?
2)If I want to make a 2.5D \ Tile map editor what would I need to know?
as I said I know the very basic stuff, but I am no genius in coding games, that's why I came here so you can point me in the right direction.