Feed him after a short walk or romp in the yard. Give him another chance to relieve himself before you go to work. If he's exercised heavily, wait 30 minutes or so before the evening feeding. He'll need another bathroom break anywhere from 30 minutes to several hours after the evening meal, depending on his age - it'll be your job to figure this out. He should get another airing right before you go to bed.
Rescue dogs come from a variety of backgrounds, but all dogs can do with more socialization.
Now you can start inviting your friends and relatives over. Do introductions to new people gradually. Introductions can take the form of petting, playing fetch, even going for a walk. Don't reach for the dog right away - let him come to them. If he does not go to the new person, that visitor should completely ignore the dog.