First, let's debunk the myth the you only have to worry about keywording if you are a stock photographer - NOT TRUE!
If you have a blog and/or website search engines will "spider" them on almost a daily basis and if your images don't have titles, descriptions, and keywords you have just missed a golden opportunity to be listed in the millions of searches that are going to be conducted on any given day.
And to be clear, I am not talking about just the photographs you post, you should tag every image (borders, headers, backgrounds, etc.) that make up your website as well.
Here are some articles that you should (seriously) consider reading:
1. Effective Photo Keywording Step by Step (Photopreneur)
2. Photo Keywording 3.0 (Photopreneur)
3. Keywording for Stock Photography (Story Hour Photography)
4. Keywording and Broccoli, Parts 1 & 2 (Keyword Compiler)
If you want to get an idea of what other folks are doing with regards to image tagging there is a waaaay cool tool from Yuri Arcurs (the undisputed king of microstock photography) that allows you to search shutterstock for images similar to yours and then see how that image was tagged by its owner.
I am not suggesting you "steal" from others, but if you are new to the task of tagging and keywording images this could help you better understand how the process works.
And finally there is a free tool called iTag that will help you automate the process of embeding titles, descriptions and keywords into your images.
