"Professional" is a broad term. A better idea would be to find a style that works for you and run with it.
For me, I have an odd love of title screens that appear to take place in the world itself. Observe the title screen for my off-and-on project:
For all intents and purposes, it's just another map. The girl sitting on the bench enforces this. (There are also butterflies and squirrels and birds floating about, but it's hard to capture that using Print Screen.) It's my style, though, so that's how I do things.
Experiment a little and you'll find your on way or something.