Yes, in on-page optimization, you have to make sure that your main keywords are on main places.
These are main place I think as well:
Title
Heading
Description
Image
Body (use 2 to 8 percent density)
Bold your main keyword in body part!
There is also density and length limitation in title mainly (it should be 25 to 40 percent and within 60 characters).
Apart from all these, the content should be fresh and qualitative also for better result.