First off, i would like to say that Dead Man's Booty is probably the easiest challenge zones than any other challenge zone (Do not underestimate the power of Spring Beans). And you could probably get a higher score in this challenge zone than in any other challenge zone.
All the zombie-killing techniques and the plant strategies are in the specific plants/zombies' section.
Extremely Mandatory Plants
You might think it's just like planting 2 sunflowers. Think again - You're wrong! Twin Sunflowers are the "source" of your defense. Try to protect them as much as possible. Plant these in unfinished rows because there's not much zombies in there.
So experts don't use sunflowers in high levels like 30+. But sunflowers are quite important - Try to plant them next to Twin Sunflowers to defend them. Using Sunflower as a sheild for Twins is better than using a Wall-nut, and thanks to the 1.7 update, it now acts like a Twin Sunflower. Use these are a distraction for zombies who are already eating your strong defenses.
DO NOT UNDERESTIMATE THE POWER OF THE SPRING BEAN! He's quite...or should i say extremely useful for early Swashbucklers and early zombies (Especially the Bucketheads) And you know what's so powerful about this little plant? It can insta-kill a gargantuar! You're unlucky if you're in a level with gargantuars and not much "unfinished" planks.
A Cherry Bomb is actually better than a Coconut Cannon - Use this for early zombie crowds when you're defenses are not finished yet.
Everyone knows why. Put this in second or third square.
Pea Pod (when it has all 5 heads.) can shoot really fast and quickly kill all the imps launched by a gargantuar or a cannon. It is recommended to put 2 of these in the first 2 squares and a winter melon in the third square.
This can acutally come in handy than a Squash, use this for early zombies when your spring beans are still sleeping or recharging. Chili Bean is also for early Seagull Zombies.
Than spending all your virtual coins in Plant Food, just spend sun for plant food. (I don't have this plant, i just think it might be useful!)
You can replace Chili Bean with Coconut Cannon for a deadly combo with Winter Melons or Pea Pods.
Can be a Chili Bean replacement.
As funny as it sounds, this zombie can be pain in the "brain." He's really tough for a one-headed Pea Pod. Chili Beans can deal with early Seagulls.
Gargantuars can be really overwhelming when he destroys most of strong plants, and that's why Spring Beans are really powerful. When there not near water, try to stall them by putting cheap plants in front of 'em like Chili Beans, Wall-nuts, or Sunflowers.
The imps are the most annoying of them all. Try planting Chili Beans in the 3rd square of full rows to easily kill them and stun the backmost zombies. Take care of Imp Cannons by using Cherry Bombs.
One of the source of the annoying Imps, Try putting Spring Beans to get rid of the barrel, even when he's not near water, it can help because it will push away the barrel he's rolling.
His zombie parrot can be extremely annoying, try to kill him as quick as possible. (Fun Fact: Using Cherry Bomb to kill a zombie parrot burns the parrot to a normal zombie ash, that is because it has no "ash" image.)