In the bookstore, go straight for the magazine section. Check out the tattoo mags. You'll be surprised at how many tattoo magazines they have now days. Flip through and take note of the various photographs and designs displayed in the magazines. This can be a great source of inspiration in finding your ideal design.
Next, you can check out the books and see what they have. Sometimes you'll uncover old tattoo books with real cool old school designs. You may come across some other more modern books that will explain meaning and symbolism for each tattoo.
On the Internet
The internet is an easy and excellent place to find some of the best pictures of tattoos. But, you can get overwhelmed and exhausted doing Google searches for design ideas. Here and there you'll find an interesting design, but you usually have to wade through dozens and dozens of average designs you've seen before.
Find a tattoo gallery which you can sign up for and then get access to the best tattoo designs available on the internet. This saves a ton of time and frustrations, and you will get direct access to the highest quality designs available online.