Can't seem to get your main character to be interesting, to jump off the page? Having problems with other characters who seem too ordinary?
Try this: Imagine that your character will visit you for the weekend. What activities would you do? How funny is the character? What secrets do you learn? Does he drink? How much? Does she smoke? Is she a flirt? How do your friends respond? Would you let him babysit your child? Would you let her date your college-age son? What stories does the character tell? How does she surprise you? Can you trust her? Does he make you fearful? Does she shock you?
If at the end of this imaginary weekend you don't look forward to another visit from your character you need to upgrade your character's personality, uniqueness, weaknesses, gravitas, etc. Remember, most books are too long to read in one session, so your reader has to look forward to coming back to the book and spending more time with your characters.