I agree that you should make sure that no UTI infection is an issue.
Dogs are creatures of habit. They depend and look forward to schedule. For instance my three dogs go out in the a.m. around 5:15, breakfast around 7:00a.m., they have a mid day potty brake around mid day, afternoon walk around 3:30, dinner around 6:30, last potty call around 9:00.
This takes place every day, and they know very well that it will happen.
You also need to pick a house training system and stick with it, don't switch or you will confuse you and your dog. Your dog won't be considered house trained until there are no accidents (aside from illness) for at least 9 months, this needs to be your goal and doing what it takes to get there.
There are numerous systems posted here that will help you, I have a 5 step program that helped me and lots of others. If you want it, let me know and I'll post it.
Good luck!
Anela