The way I got Jaxson who is 5months old fully house trained is strict routine! He had to earn trust & learn to go outside which he did in about a 2 weeks.
He still stays in a big play pen at night just so I know he's safe cause he's still a puppy & i'm afraid he might get into something without me hearing him. I'll post his schedule for you as well.
7am-Breakfast/Water
7:30am- Potty Time!
8am- 30minute play time
8:30am- Potty Time!
9am-PlayPen (so I can clean the house...etc)
10:30am-Training(Sit, Stay, Lay, Come etc)
11am- Potty Time!
11:30am- Lunch
12pm-Potty Time!
1pm-Play Time.
1:45pm-Potty Time
2pm-Nap Time
5pm- Dinner
5:30pm-Potty Time
6pm-Play Time
7:30pm- PlayPen
8:30pm-Potty Time(Last time for the day)
9pm- Bedtime! He sleeps all night no problems!
That is his schedule/routine & he has never had any problems and we got him at 12 weeks he's 18 now.
We do let him out a little longer to kinda roam the house with supervision. He is a good boy & he loves his schedule!