Sometimes the best reference books are your textbooks!
Now I haven't really mentioned much about my textbooks for my classes because I hardly take any classes on my own other than a few classes here and there, but I spent a few weeks preparing for my midterm (which is now over whew!) I have other books in my library (I like books) but this is really the best book out there for sewing reference.
The Reader's Digest New Complete Guide to Sewing is really good. It has good illustrations and instructions on how to do sewing based on projects that you would want to do. It is also good because it shows you what project the book decided to print out and you can buy them (or in my case, scan the preview patterns for patterns later.)
For my other reference book I have DK's Complete Book of Sewing in my library before. It is a good book, but in a different way. It is a more hands on on techniques out there instead of project based and then show techniques. It is a good book but for a different reason.
I hope this will help any future sewers with these 2 books as starting points. Sometimes when you are stuck or need inspiration reference books is usually where I go look.
I am going to do a bunch of muslin work now. Sometimes you just need to make a bunch of muslins in order to make a final project. I will tell you more about muslin work later when I am done with some.