https://sims4studio.com/thread/9/blender-tutorial-links
If you feel like you'd prefer to start learning by doing I've written a basic beginner's meshing tutorial that shows how to create your own accessory for Sims 4. It goes over each step with illustrations and questions are welcome in the thread. That tutorial is here:
If you feel you need to get a handle on some basics before diving into meshing read on
This is a list of some good Blender tutorials I've found around the 'net. While they are not specific to Sims 4 they are valuable tutorials that will help you learn to make things for the game. So far all the tutorials on the list are video tutorials. If anyone wants to share the link to a tutorial for Blender that has helped them feel free post it in this thread.
Interface and Navigation: cgcookie.com/blender/lessons/interface-and-navigation/
Meshing: cgcookie.com/blender/lessons/3-modeling/vimeo.com/channels/blendervideotutorials/44837735 This link has pages of short tutorials showing various things needed for meshing.
Intro to Blender Modifiers: www.blenderdiplom.com/en/tutorials/all-tutorials/406-ressource-blender-modifiers-explained.html
How to duplicate items in Blender (Object mode and Edit mode):
If you're unable to center Blender's scrolling on the model: