Make sure your yeast is fresh. Active dry yeast, sold in individual packets, is the easiest type to use, and keeps well in your pantry. There is always a 'best if used by' date on the packages, and you should follow this rigorously. If you are going to take the time to make bread, fresh yeast is essential.
Cake yeast, if you can find it, really makes a wonderful loaf of bread. This form of yeast is fresh, stored in the refrigerator, and is very perishable. When you buy it, use it within 1-2 days, or it may mold.
The temperature of the water, whether used to dissolve the yeast, or added to a yeast/flour mixture, is critical. Until you get some experience, use a thermometer. When the yeast is dissolved in the water or other liquid, the temperature must be 110 to 115 degrees. When the yeast is combined with flour and other dry ingredients, the liquid temperature can be higher; about 120 to 130 degrees.
The flour you choose for your bread also makes a difference in the quality of the final product. Bread flour makes a superior loaf. This flour is higher in protein content, and protein, or gluten, is what gives bread its unique texture.
When water is added to flour, two proteins, glutenin and gliadin, combine to form gluten. Gluten forms a network of proteins that stretch through the dough like a web, trapping air bubbles that form as the yeast ferments. This creates the characteristic air holes of perfect bread.
All purpose flour will also work just fine in most bread recipes. Don't use cake flour because there isn't enough protein in that type, and your bread will fall because the structure won't be able to withstand the pressure of the gasses the yeast creates.
Whole grain flours and other types of flour add color, texture, and flavor to breads. These flour types don't have enough gluten to make a successful loaf on their own, so all purpose or bread flour is almost always added to provide structure.
The type of liquid you use will change the bread characteristics. Water will make a loaf that has more wheat flavor and a crisper crust. Milk and cream-based breads are richer, with a finer texture. These breads brown more quickly because of the additional sugar and butterfat added to the dough. Orange juice is a nice addition to whole wheat breads because its sweetness helps counter the stronger flavor of the whole grain.
Fats like oils, butter and shortening add tenderness and flavor to bread. Breads made with these ingredients are also moister. Make sure you don't use whipped butter or margarine, or low fat products, since they contain water. The composition of the dough will be weakened, and your loaf will fail.
Eggs add richness, color, and flavor to the dough and resulting bread. Egg breads have a wonderful flavor. Sugar is the fuel that feeds yeast so it ferments, producing carbon dioxide that makes the bread rise. Some bread recipes don't use sugar, but depend on sugars in the flour to provide food for the yeast.
Salt is essential to every bread recipe. It helps control yeast development, and prevents the bread from over rising. This contributes to good texture. Salt also adds flavor to the bread. It is possible to make salt-free breads, but other ingredients like vinegar or yogurt are added to help control the yeast growth.
Toppings can change the crust of the loaf. Egg glazes are used to attach other ingredients like nuts or seeds. An egg yolk glaze will create a shiny, golden crust. Egg white glazes make a shiny, crisp crust. For a chewy, crisp crust, spray the dough with water while it's baking. If you brush milk on the dough before baking, the crust will be softer and tender. Brushing the baked loaf with butter will also make the crust softer. Enjoy experimenting with toppings and the recipes!