Roadhog is my main, I can help you.
The BEST tip to play Roadhog is: don't waste your hook. Use it wisely, and against the best possible target, "best possible target" means, for example, the enemy support, a squishy annoying DPS (Tracer, Sombra), an enemy who is ulting, you basically troll the enemy if you hook him/her while ulting.
Also, as a Roadhog main I get very tilted when I see those braindead Roadhogs who use their self heal AT THE SAME TIME THE SUPPORT IS HEALING THEM xD
Don't waste your E, the self heal. If you are being healed by the support, save it, you are going to need it.