Go into your Control Panel, and enable "Rich Text" editing. PLEASE don't go overboard with text formatting... it makes the posts very difficult to read and follow.
With the rich text editor you can:
It works just like a word processor program:
If you're feeling very advanced, you can try the advanced mode:
There are popup windows to choose your colors:
And an easy popup box to choose an externally-hosted image to insert:
And more. We hope that it will suit your needs.