Design Reference Links are always useful. Below is mix of bookmarks I recommend. There are plenty more links but these are a few I find useful.
NEWS AND INDUSTRY INFO
Daily Graphic Design Related News
Creative Packaging Design
I Love Typography
Website Resources Centre
*Be sure to read each set of terms, mix of personal, donate and free
Kuler (Colour theme creator from Adobe)
Website (Browsers) safe area
* Create your own templates in photoshop, illustrator etc so you always start with a reminder on constraints.
Copyright Proofing Marks
Placeholder Text Generator
*more solid links found at designerstoolbox.com