One tired mama

Hey guys I am one tired mama looking for some help. I am a first time mom with a 7 month old who wont and has never slept through the night... not even close. I put him down around 8-9pm & sometimes he will sleep pretty good for the first 4 hours then after that he is up every 2 hours until 5 or 6am. I make sure he has enough to eat everyday, he is on formula & solids right now. He plays all day long so I know he is wore out. I just don’t know how to get him to sleep longer! Is there anything that has worked for you???