Keep it simple.

Subheads should be simple and direct. Avoid the temptation to use tricky wording.

Think of signs on the highway. They have to be short and direct because when we are driving by, we only have a split second to read them.

They just give us the information we need: Next Exit 12 Miles. Rest Area 3 Miles.

Your subheads should be like those highway signs: short, informative, and reassuring.

Note that some style guides (APA for example) have guidelines for subheads (use of capital letters, underlining, etc.)

And one more thing.