Here are some moist cake threads:
http://forum.cakecentral.com/cake-decorating-ftopict-95251-.html
If you scroll down there are also threads on simple syrup: How to make it, how to apply and how to flavor, with recipes.
If it's a butter cake that came out dry - here's a troubleshooting thread:
http://www.joyofbaking.com/ButterCakeTroubleshooting.html
Here are multi-linked threads on doctoring cake mixes:
http://forum.cakecentral.com/cake-decorating-ftopicp-2047091-.html
Includes info on: pudding in cake mix, tips on add-in's, dream whip, meringue powder, secrets to fluffier cake and all the extender and enhancer recipes.
To make sure you're filling the pans with the right amount of batter, and baking at the right temp. and time:
(Wilton charts that give this info.)
http://www.wilton.com/cake/cakeprep/baking/times/index.cfm
Also, I would recommend using bake-even strips. 
HTH
You could also try using a flower nail as a baking core. You don't normally need one for a cake that size, but it will help it bake more evenly. Are just the edges dry, or is it all the way through?
I've started baking everything at 325 F, then time it for 5 minutes less than I expect it to take. I check it frequently in the last few minutes to make sure I get it out as soon it's done.
Also, look in the recipes file (I don't know how to link it) and look for the extender recipe. One of the other CCer's told me about it and I LOVE IT!!
I use the Vanilla Yogurt instead of the sour cream, and i only put 1/2 cup white sugar, instead of the whole cup. But it makes my mix cakes dense and moist. I also use a mix with the pudding in it. But I have found that the extender really perks it up.
Have fun with it!!
I use betty crocker and follow the directions on the box. Sounds like your oven temp may be too high. I strongly recommend the baking strips .... they help promote even baking so the corners don't get all baked and hard before the center gets done.
I also use Betty Crocker cake mixes, bake even strips and I also use milk instead of water in my recipe (I also add Hershey's syrup to my Chocolate Fudge cake). One of the tricks I have found to make my cakes even moister is after it has cooled, wrap it in plastic wrap, stick it in a plastic bag to seal it and put it in the refrigerator at least over night. I have found that my cakes are even moister than just leaving at room temp. and icing them.
Thank you all for the advice: i switched the oil for mayo and the water for milk and I lowered the oven temp to 325 though I will admit I did a test cake first and undercooked it by 10 min but the order cake turned out beautifully and didnt rise so much in the middle. 
Quote by @%username% on %date%
%body%