Your avatar is the first thing people see about you, so you better make it stand out from the crowd.
One of the best suggestions is to have a photo, that clearly shows your face and change the background to a solid color or a gradient. You can do it on your own or use a couple of tools to enhance your avatar.
The cover is the second component of what makes the first impression about you. There are a lot of tools online that can help you build creative covers for your profile. We will mention just a few ones that can make your banners dynamic.
Remember that your cover should provide as much info about you as possible. Show off your achievements, your vision, etc.