Changing object properties
You can always change the colors of a textbox using the Properties window. When the form is in the Source window, click on the textbox you want to change. You'll see some small "squares" on the edges of the textbox, which tells you Visual Studio has set the focus on that textbox.
Now look at the Properties window in the lower right corner of the screen. (If you don't see it, press the F4 key to call it up.) If you scroll the Properties window, you'll see properties for BackColor and ForeColor. If you click on the righthand column, a dropdown arrow appears. Click on that and you are presented with a list of three tabs (Custom, Web, System) with color choices you can select. The Web tab presents the widest selection. You should be able to select a color combination that you like.
As I mention in the book, Microsoft has spent more money than you and I'll make in a lifetime figuring out User Interface (UI) objects and colors. While it's fun to experiment and explore different colors and learn how to change other properties for user control objects from the Toolbox, my advice: stick with Microsoft's choices for your defaults.
Jack Purdum, Ph.D.
Author: Beginning C# 3.0: Introduction to Object Oriented Programming (and 14 other programming texts)