If you are brand new to Illustrator, start here: How To Get Started With Adobe Illustrator CC – 10 Things Beginners Want To Know How To Do
How To Use Adobe Illustrator (Short Videos on Basics)
Adobe Illustrator: Using the mesh tool (Creating an apple)
Adobe Illustrator Tutorial: Compound Paths & Clipping Mask
Illustrator Pen Tool Tutorial – Part 1
Illustrator Pen Tool Tutorial – Part 2
The Bezier Game: Master the Pen Tool!
Adobe Illustrator Tools and Techniques for Logo Design
Illustrator CC CS6 Tutorial – How To Use The Blob Brush
Creating Complex Shape Using Object > Expand and Pathfinder Tools
General Instructions for Grouping and Expanding
Using the Appearance Panel (video)
Pathfinder (also: Shape Builder and Pathfinder)
Compound Paths and Clipping Masks
Pattern Maker (good instructions, not-so-lovely pattern…)
Image Trace for photos (all four pages), or Image Trace for artwork.
http://design.tutsplus.com/series/guides-to-illustrator-tools–vector-4892
http://design.tutsplus.com/tutorials/illustrators-pen-tool-the-comprehensive-guide–vector-141
http://veerle.duoh.com/design/article/illustrator_eraser_tool
http://pwg.deviantart.com/art/Illustrator-Tutorial-Pen-Tool-8955073
http://school.tatoland.com/illustrator/aipentool.html
http://www.illustratortips.com/index.php/Instruction/Intermediate-Tips/drawing-a-cartoon-face.html