Some downloads may come with a 'Readme' or 'RTFM' text file - read that as well! Please don't come running to me complaining about how a mod broke your game because you didn't read the documentation, because it's not my fault that you didn't read instructions. If a mod gives you specific instructions on a special place to install it, or some 'Do's and Don'ts', read them. This is mainly to list annoyance fixing mods that other people might benefit from.
This is a personal list of recommended DLC for The Sims 2.