If you plan on visiting more than once in a season, you're probably best off buying a Season Pass (Play Pass) for the park (see Resource links for more information). It pays for itself in just two visits, and includes a coupon book with bring-a-guest-for-free tickets. A Premium Season Pass has the extra benefit of additional coupons and additional free passes.
Consider getting a season parking pass as well, if you plan to drive.
If at all possible, go on a weekday. Weekends are more crowded (but not unbearably so, except for some holiday weekends).
No matter what day your visit, try to get there early. The whole park experience is simply more enjoyable earlier in the day, before the crowds arrive, the weather heats up and the parking lot fills up.
If the weather is looking hot, definitely plan for the water park. Bring a bathing suit, and easy-on, easy-off footwear (the ground get HOT! some days). Do the big rides, like The Tornado, early, before the lines build, then spend the hotter part of the day enjoying the giant wave pool, and other water attractions. You'll probably want towels as well, though we've had toweleless drip-dry days with no problem. If you have a season pass coupon book, look for the free cabana coupon. This is a very nice option, but without the coupon, it costs more than a hotel room!
Securing your valuables at the water park takes some planning, as you don't want your wallet to get soaking wet. I just lock my wallet in the car, and carry whatever cash I'll need for the day (which can get wet with impunity). You can buy a wallet-sized waterproof carrying case in the park' s gift shops, or rent a locker for the day (neither are particularly cheap, though).
Six Flags has some great roller coasters. Again, lining up early in the day is the easiest way to get on board. I like Superman, Ride of Steel the best as it's tall and steep and fast, like any good coaster, but doesn't turn you upside down or shake your brain to jelly. My kids are fond of the Batman ride, the Joker's Jinx, and the two old fashioned rides, the Wild One, and the Roar.
You can bring water into the park, and I always carry several bottles. You can also buy a souvenir soda cup, and get endless refills all season for one dollar per refill. It's one of the rare good deals.
Eating at the park is pretty expensive. The thriftiest option is to bring a cooler in your car, and have a picnic lunch in the parking lot (make sure to get your hand stamped for re-entry). The pizza family meal deal at Papa Johns ($10 off coupon in the Season Pass coupon book) will feed a hungry family of four, and can handle five as well.
The park has several stage shows. The Wild West stunt show in Coyote Creek is a favorite with kids (but if you've seen it once, you've seen it all). There's song and dance, comedy, magic, and others as well. A few are indoors, meaning air-conditioned, which is always welcome.
There's also a nice kiddy section in the park, with miniature versions of some of the rides, and a familiar Looney Tunes theme.
Leave about 1/2 hour before park closing time, if you want to avoid the end of the day traffic jams.
Check the online calendar for special events. The park hosts many free concerts and events, and it helps to know the details before arriving.
