Can I get some tips on house breaking?

I have a 6 month old pit bull terrier mix I take him out to potty every hour or if he acts like he has to go. If I see him peeing in the house I tell him no firmly and take him outside to potty. Also when he is out and does go potty I say go potty and tell him good boy. If I am going to take a shower I will takehim out and let him go potty then leave him in the living room normaly my mom is in there with him and every time after I leave he pees on the floor right after I just took him out! He just got nutered a week ago so I had hoped that would help the peeing problem but it hasnt does anyone have any more tips?