I can't really answer this as to the thread colors to choose...
I started by doing alot of things that called for mostly blues and greens...
I have added to that and now have close to 200 different colors.
Most of the thread I use is Madiera and Sulky, just because it is easy to come by and cheap with the Joanns sales...
I also purchase bobbin thread, black and white in large spools and have found to purchase black, white top thread in large spools.
I do not use prewound bobbins..
Just my 2 stitches...
Kirsten