Between several cooking articles on the subject, and my own efforts in the kitchen, I came up with the following tips for a better soufflé:
1. Always make sure your egg whites are “clean.” Any residue from the yolks will allow air to escape, which will inhibit the mixture from rising. The best way to do this is to use three bowls – one for the yolks, one for the egg whites, and one for collecting the egg whites once cleanly separated.
2. Use salt and cream of tartar when you beat the eggs. This will strengthen the mixture and enable it to rise evenly.
3. Generously butter the mold, and dust evenly with either sugar (sweet) or breadcrumbs (savory). The sugar or breadcrumbs will help the mixture to rise, and prevent it from sticking to the sides of the mold.
4. Refrigerate the buttered molds until needed. This will prevent the butter from sliding.
5. Avoid the bath. Some recipes call for a water bath, but the bath is really just a hassle.
6. Fold the egg whites in quickly with a rubber spatula. The mixture should be well-mixed so it rises uniformly.
7. Set the soufflés at the bottom of the oven. The proximity to the heat will create a greater puff.
8. Do not peak! Opening the oven prematurely will lower the oven temperature and interrupt the baking process.