Hello Leonard. Have you had anyone read and critique your work? First and foremost, I would suggest having someone familiar with your target genre read your work and give you honest feedback during the final re-write phase. It should be someone who will not pull any punches and understands the critique process isn't the same as a pat on the back, it's a valuable tool that helps you see the elements of your work that only a reader will notice.
After that, when you have the final manuscript polished, get another critique before beginning the quest for an agent. You want to be sending out your very best work when you query an agent.