1. Make sure you have a good reason to buy a DSLR.
Unless you have deep pockets, there should be a genuine purpose for buying your first DSLR camera. Even an entry-level DSLR with a lens will cost $500-$600, and four times that much for a mid-level model, plus the cost of a lens. For example, a full-time photography student pursuing a degree or a serious amateur that aspires to be a semi-professional each have a good reason to buy a DSLR.
2. Follow the “lens first, camera second” rule.
The pros know that the lens is the most important member of the camera/lens team. You pick the right lens according to what kind of photos you want to take. Close-ups, portraits, landscapes, sports and nature all require different focal lengths, some of which may be found on a single zoom lens. Once you've chosen the right lens, you then buy a compatible DSLR. Some of my personal favorite lenses include 24mm for landscape photos. 24-70mm focal length is great for landscapes, portraits and great all around “always have with you lens”. 70-200mm is a must have in any camera bag, this lens can be used for all of the above and is great for getting in tight. When you are first getting started, a less cost alternative to this focal length would be the 18-200mm which is a fantastic lens.
3. Ask your photo buddies.
Seek recommendations from people you know that already own a DSLR. Ask them to show you their cameras and explain why they bought that particular model. Accompany them on a photography trip and take a few pictures to experience a DSLR in your hands. If you don't have any photography buddies yet, joining a photography community is a great way to meet like minded people who share the same passion as you do in photography.
4. Go online to learn about the various DSLR models.
Once you've started to narrow your choices of a first DSLR, search the Internet, where you'll easily find numerous articles and reviews of every DSLR on the market.
5. Rent first, buy smart.
Before spending hundreds, even thousands, for a DSLR you may not like, spend a mere fraction of those numbers to rent your “finalist” DSLRs, one per weekend. You're virtually guaranteed to find the camera that feels good in your hands, that you find easy to operate and take great photos and is a good investment for your money.