Best tip: arrive early, especially if enjoying the bigger slides is a priority for you. Lines will be shortest first thing in the morning.
Consider renting a cabana. I think they are a great value (especially in comparison to their Disney counterparts, which are $320

). I don't know when you are travelling, but offseason prices are often as low as $59 and they are an awesome splurge. They include your own fridge and locker, rental towels, and 12 bottles of Dasani water. And having a private space to kick back and relax is fabulous.
If the budget won't allow for a cabana, there are a ton of HUGE umbrellas with loungers on the sand beach, and they are free (first come, first served). Arriving early will allow you to get the best pick of location.
Our favourite area at Aquatica is Roa's Rapids. Its a tubeless lazy river with a very fast current that is more fun than you can imagine. Its best enjoyed (even for adults who are good swimmers) by wearing one of the many life jackets which are available at the entrance to the rapids. Then wade in, and once you hit the current, pick up your feet and let it carry you around (and around and around and around!). We literally spend HOURS there on each of our visits, and hands-down its the best waterpark feature we have found anywhere. There's nothing else like it!
For "best value" dining there's the all-you-can-eat buffet at the Banana Beach Cook-out. Two different options are available...one visit or an all-day pass....and they offer pizza, barbecued chicken pieces, pulled pork, hot dogs, watermelon, brownies, warm yeast rolls, coke products, and more. You can add a refillable cup to your all day dining for $5, with refills costing about $1 thereafter. The cup is also good for refills at SeaWorld and Busch Gardens, and unless things have changed since our last visit, its also good for the refill program at the Universal parks.
For dining, there's also the Waterstone Grillwhere you can get chicken tenders and fries, grilled hamburgers, salads, etc. all ordered a la carte. The SeaWorld parks are generally pretty strict about bringing in outside food so plan to buy your food and drinks there rather than bringing in your meals in a cooler.
Aquatica has some great little popcorn buckets that are also sand castle pails. You pay an initial price of about $6 for the bucket (filled), with refills in the $1-$2 range. Again, the refill program is good for the life of the bucket (you can bring it back trip after trip and just pay the refill price) and again, its also good for popcorn refills at the other SW parks.
The trainers do short sessions with the Commerson dolphins throughout the day that are fun to watch. They take questions from guests and are really worth taking part in at least once during your visit. There's also a large underground viewing area where you can watch the dolphins play during the non-training session times.
The kids area at Aquatica is HUGE and so colourful and fun. Your boys will probably want to spend a good amount of time there, just splashing around

.
This thread has a whole host of my Aquatica photos, if you want to take a peek:
http://www.disboards.com/showthread.php?t=3127667
If there are any specific questions you have, feel free to ask!