1. Create repeatable background images:
To decrease the file size and to make the website lighter use backgrounds that can be repeated vertically, horizontally or both. Try to avoid huge images in background which can take more time to load compared to repeatable image.
2. Avoid excess use of gradients:
Gradients can’t be created using CSS2 so when more gradients are used more number of images needs to be used which can increase HTTP requests resulting in increased load time.
3. Never use gradients in borders & text:
Always use solid colors in borders (strokes) and text
4. Don’t use Sharp Text for Content:
Sharp text can be used for heading but not for content.
5. Don’t change the layer mode:
It becomes difficult to so save a layer with different mode other than Normal.
Source : https://experiencedesignideas.wordpress.com/2012/11/27/top-5-tips-for-visual-designers-for-better-designs/