I'm posting some links to some helpful tutorials -- because I think I might need them later and be unable to find them in my humongous Bookmarks folder!
Installing Downloads
The Last Ever 'How Do I Install Downloads?' Tutorial by BeosBoxBoy. He says it all better than I ever could!
Running Sims 2 on a Widescreen Monitor
Increasing Resolution for Win 7 For Windowed Mode
Avoiding Hood Corruption
UV Map Tutorial
The version for Custom Meshes allows you to extract a mesh and view its UV Map. The UV Map can then be used as a layer in a PhotoShop file to help skin or recolor a mesh.
Note: The newest version of UVMapper won't save the UV maps because they want people to buy their proggie. If you click on the UV map and press Ctrl-A to select the entire map, you can Copy it and paste it into your favorite paint proggie.
Gothplague's UV Map Tutorial
Skintones:
Zirconia Wolf's Tutorial to Make Skintones Use the Adult Mesh For Elders
Tired of droopy boobs and saddlebag thighs? Upgrade your favorite skintones to use the adult meshes for elders!
A more general skintone/custom mesh linking tutorial
Theo's tutorial
Save file size by reusing the default skintones (or any custom skintone): thetigerking's Skinless Skins Project 2.0 and Chris Hatch's Skinset Templates
Pixel Perfect Skintones, another BeosBoxBoy tutorial, to maintain the image quality when importing textures. Helps with blurred objects too!
Making Your Own Maxis Clothing Hiders/Unhiders/Recatagorizers
Zirconia Wolf's Version
Phaenoh's Version
Maxis BlockFoot meshes to fix your ruined outfits
Tutorial is on the last page, or you can use Gothplague's tutorial and these meshes. Also helps fix bare-toed XHi-Res Warlokk meshes.
Fixing Blue Flashing Accessories
Inge's method for how to move the produce of puppy-kitten mills to other 'hoods which is also a sensible way to deal with the zillions of Maxis produced strays!
50-50 Method for Finding Bad Downloads
Although it sounds laborious and picky, once you do it, you'll never be afraid again!
Using the PhotoShop DDS Plugin for better image quality
Categorizing and Townifying Your Clothes
Wall bump mapping -- yes, your walls can have real texture to them!
Zirconia Wolf's tutorial for Binning Hair with CatOfEvilGenius' Binning program.
Organizing your Lots Bin -- so easy, just renumber your files!
Final Still In Progress Fix -- when your Sims get stuck at their finals, zephyrzodiac (with help from Trif et al.) tells you how to fix them!
Custom Icons for Accessories
MilkShape:
Previewing object recolours using Milkshape 3D
Age converting clothing meshes -- Fixing the neck
Creating clutter from game meshes
Sim Modification (outside the Game):
Permanently Changing a Sim's Height
A tutorial on how to change an adult Sim's gender!
A combination of SimSurgery and BodyShop to tidy up the mismatched clothes and such...
Warning: Gay Sims Club 2 is for persons over 18 only.
Giving your in-game sims a permanent make-over by Wirelessguy
A similar tutorial on a non-adult site.
Object making:
Adding a subset to an object (and making it recolorable)
Making Wall Objects Shiftable
Fixing oversize clickable area
Object recoloring tutorials:
The tutorial I learned to recolor from, start to finish
One with more emphasis on manipulating the textures
Recoloring Seasons-Compatible Trees