Make Buttons Identifiable
In this above example this button has a background that’s using gradient. However, it looks blurry and worse with a shadow. The white lettering is also hard to read. It should have more contrast and simplicity.
Keep Buttons and Patterns Simple
The above example is a much better display of buttons being properly used. For instance the lettering is in bold. The space around the lettering is wider as well. Although the buttons are not identical in color the button patterns show they are partners.