Your Facebook and Twitter cover photo is your largest lot of real estate. It's the first thing people see when visiting your page. Why would you want to waste that? There are a few key things you can include on your cover photo to attract more clients and create the kind of culture you want on your page.
Have a picture of you! People don't connect to your logo, they connect to people. You are the face of your business. Make it a welcoming photo that shows a bit of your personality.
Have a blurb about what it is you do. Health Coach? Say that! Are you restaurant with a famous dish. Let them know about it! Have a special free offer Tell them to click on the photo and put the link in the comments.
Keep it neat & tidy. Try not to overwhelm your followers. Keep the photo clean & easy to read.
The idea is to allow people to connect with you and know all that you're about by just glancing at the very first photo they see. You have about 7 seconds to grab someone's attention - just enough time to scan over your cover photo. Show them who you are and what problem you solve.
In conclusion, keep it personal, simple, tidy, and offer a solution.