Dear New: Certainly I will help you. To answer about textures and how I use them, I can give you an overview of what SketchUp can do with photo textures, and point you to resources that will teach you how to do it, too.
I only project a texture when necessary; otherwise I simply import the texture and stretch it over a face (using the pins found in the context menu)... then I choose "make unique texture" (also in the right click menu). This trims all the invisible parts of the photo, leaving only what is visible on the face, thereby reducing file size. For curved surfaces such as domes, I project textures (also found in the right click context menu). See my post about the Griffith Observatory model for an example of this.
SketchUp 7 has two handy tools besides "make unique texture," the first of which is "combine textures." This allows you to select two unique adjacent textures, such as a wall and a window, and combine them into one. It can even automatically remove the geometric edges which previously divided the textures. The second is "edit texture image" which opens the texture in an image editor and automatically reloads the texture in-place when you are done editing. I always edit out peripheral objects such as trees, cars, and pedestrians.
As far as my sources of photo textures, I either take the photos myself (retaining the copyright) or else I use Google Street View images, to which Google holds the copyright (and then I give credit). In some cases I paint textures myself to resemble photos if none are available to me. In cases where I use photos found elsewhere on the web I make sure to use only those in the public domain or else get permission from the creator to use their work. I think it is important to respect the creative efforts of one another.
For detailed information on how to use textures in SketchUp, there are many online tutorials. Have a look at this page which is geared towards beginners: SketchUp Help. I also have a link in the sidebar called Make 3D SketchUp Models Now which will help any beginner get going on their SketchUp modeling career!
If you have any specific concerns about how to use textures, write any time.
