Recolouring Recolouring/retexturing sim content like clothes, hair, skintones, eyes, etc.
Meshing Change body shapes and create new clothing meshes.
Modding Default skins and eyes, townie-friendly stuff, etc.
Sims Creation of the sims themselves, including celebrity/character sims.
Recolouring Recolouring and retexturing objects.
Meshing Creating all new 3D object models and everything related to them.
Modding Changing the way objects work.
Building Building the perfect lot or house - all the cheats, tricks, and tips.
Landscaping Making the most of your gardens with planting and architectural elements.
Walls & Floors Making walls, floors, and ground cover.
Careers & Majors Creating new jobs and majors.
Hacks & Game Mods Creating hacks and other game mods.
All Tutorials View a big list of everything.
Please start with the level you feel most comfortable with, or if you are a total beginner, see Sims 2 Modding Start Here