I got into reviews after I won a giveaway on another blog!
I don't think many people know about that- but often if you win a giveaway on another blog the company that sent you the free product will ask you if you'd like to review it on your site, or do a giveaway. It works out great for the company- because you were already getting a free product from them- and then they get to promote on your site as well. And works out good for you, becuase as you do reviews more companies will contact you. In my experience it's a cycle...so now you have extra reason to enter giveaways on other peoples sites! I'm having one now if your looking for one to enter ;)
Also, there is a great secret company run by TX Holly (she has posted on Mom Loop before) called Business 2 Blogger! They send out a few emails a month with different giveaway oppurtunitys - and pair blogs with businesses.
This wasn't around when I first started reviewing, and I would say it's a super way to dip your toe in the water of reviews if that's what you would like to do! All you have to do to sign up, is put a button on your page. Very easy, and a great company to work with! If you sign up- tell them Shannon at MilkandCuddles says hi! There are other similiar sites out there too, but i dont use them, so I cant tell you if they work. Business2Blogger has worked great for me. Last month I got to do a review of a new Chevy Malibu for a month it was so fun :)
Their link is here: Business2Blogger
Hope that helps?