OrangeBanana wrote Tip #1.

Do not do Gun Camos. Everyone does them and it is not real graphics.

Tip #2.

Think about the people who are going to be looking at your work. Do not put a blinding neon colour that is almost impossible to read.

Tip #3.

Choose a good colour scheme.

Tip #4.

Better font choice. You need to choose a font that will go better with your image. A fancy medieval font like the one you chose does not go with a call of duty gun. You should have chosen a bold or maybe a more "cartoon" font.