Freezing is unnecessary. While people make all sorts of claims about how they make cakes "more moist," frankly I have never had a problem with dryness (only bake from scratch) and see no benefit from freezing other than time saving. When folks are saying "Wow this is so moist" or "Wow this is not dry at all" I see no reason to make them "more moist"--assuming that is possible.
I also have never had problems with dryness even with multiple days of decorating. Properly wrapped after baking and crumb coats and iced and if your recipe is good you really should not have much to worry about.
As to advice---use balanced recipes, don't over bake, consider using a simple syrup. There is plenty of information out there about what makes a properly balanced recipe. Cooks Illustrated, Alton Brown, BakeWise by Shirley Corriher are just a few of the places that discuss the optimization of recipes to produce particular results. There are also science of baking books one could read.
If your cake is only lasting a day it could easily be over baked. I do not know what test you use for doneness, but if it is--when your tooth pick comes out clean, then your cake is already over baked and will only get worse as it cools.
Dry cakes can be moistened with a simple syrup. If you are a fan of the vanilla cake you refer to, a simple syrup will add moisture (as opposed to the debate about the impact of freezing) to your cake.