For me I often feel stuck when I think of how permanent a tattoo is. I see a lot of cool designs that I like at the time but when I start thinking about the having it permanently done I start to change my mind and look for something else.
100 Guardian Angel Tattoos For Men.
Many modern American tattooist will tell you, "When you should get a tattoo, the tattoo god will tell you that it is time." Check out this article on Hawaiian arm tattoos on the site. In the 1970's, American tattooing discovered primitive, tribal tattoos. People wanted simple designs with meaning and they began copying designs, primarily from the islands of the South Pacific.
Another approach is to visit tattoo studios in your area and look at the designs and photo displays on the wall or their album to search for inspiration, but keep in mind, don't limit your imagination to what someone else already has, be creative.