If your looking for hacking tips then here's a few that I found helped on my rather excitable tank
Transitions! I know everyone says it but it does help if you never stay in any pace for too long. Certainly if he starts to get heavy do a transition (or several) straightaway.
Control the speed but use as little rein as possible. If he's allowed to trot on my lad will plough down into his forehand, if I pull to steady him he'll happily lean on me & carry on. However if I encourage him to use his energy by doing a very slow, energetic trot that I hold with my back, seat & legs he becomes much lighter & more lifted. Well timed "good boy"s encourage him to show off & can produce some quite flashy movement
Leg yield can also be useful, either to & from the kerb or across a track. By making him step across & under you engage his hindquarters & should lighten the forehand. Reinback is also useful, but only ask for a step or two then walk or trot straight off.
Don't forget that you may ride differently hacking so remember to sit up, sit back & keep your hands up! For some reason the second I leave the school I tip forward, drop my hands & hey presto my reasonably schooled horse drops onto his forehand - and who can blame him