365 Psd

This site have some free psd resources where you can know see how pros are doing button or interfaces in photoshop.
Try them by download those psd and see how they were made. Learn from their layer, and they named their layers well, try to refer to them as well.
Don't copy their work and  paste it in your assignment, I share this this for learning purpose not copy cat.
Enjoy. =)
http://365psd.com

Here is the link again:

http://365psd.com/