Flashy digital animation and special effects
If you must, use these sparingly. They are very distracting from the purpose which is to sell and show the value of your product or service.
Patterned backgrounds and black backgrounds with colored text
Try to have no more than 2 or 3 colors and use a readable font. Keep link colors consistent. This way, your visitors won’t suffer from eye strain.
Too many pages and important info is hidden
Your visitors should not need a GPS to get where they want to go. They should enjoy the trip and get to the destination easily and quickly.