The food is pretty crap, tbh, so be prepared.The Rollercoaster restaurant was once described by my nephew as being "like a bad Frankie and Benny's except your food comes down a rollercoaster" which pretty much sums it up!
The queue times on the App are often an underestimate, 90 mins on the App is often 2 hours in real life. It is worth using fast passes strategically if you want to cross off a few big rides, it breaks up the queueing. They often sell out beforehand though, so its worth booking them in advance or doing it the second you get through the gates if not.
Also the queues close at closing times, not the rides, if you are already in the queue they operate the ride until everyone in the queue has been on. So to knock off 4 or 5 big rides you need to do 1 or 2 first thing, maybe a couple in the day using fast passes and 1 or 2 in the last hour when its quietening down.
Agree with pp about 'skill' ball games when you win a bigTeddy, a lot of them are virtually impossible to win, we have several big teddy's from there, but all were the result of me paying cash to the stall, we've never 'won' one. If your DC really want one, it will be much cheaper to 'buy' one in the first hour when they give them away cheaper to get other kids pestering when they see you with one 
Some rides don't open when the park opens. eg River Rapids and Runaway Mountain Train have never in my experience opened before 11am, so if you run to a ride at 9:30 to get first in the queue and then find it doesn't open till 11 its a pita, so check the ride you want is opening with staff.
There is a tucked away coffee shop in forbidden valley that is always a lot less insane than the other food and drink places if you need a sit down and calm moment or two, and nearby, in the gloomy wood, is a ride called Duel its sort of a cross between a ghost train and a shootout (its like laser raiders at legoland but has ghosts instead of mummy's) that basically never has a queue over about 5 mins and is probably now the best loved ride of my DC (they often go round and round competing with each other), so when the big rides queues are ridiculous in the middle of the day, that might be an idea. The aquarium is also quite good for that.
All the rides (except cbbeebies) exit through a gift shop 
so have a discussion with DC first about how much you will/will not buy.
If you want a last 'family' ride all together, i'd recommend getting in the queue for the Runaway mine train just before the queue closes, so you are in the last ride of the day....the kids shout 'again' every time the train pulls back in and the ride operator (if they are in a good mood) takes the brakes off and lets them go again...my DC's record is ten consecutive loops of the track. I had to have a quiet moment sitting down afterwards until things stopped spinning.....