My best advice....Go slow. Buy 3-4 head with cash and learn on them. After 2 years, slowly increase the size of your herd. Would you rather make a mistake on 3 cows or 30?
The farmers who lose their shirts are the ones who go into deep debt for animals and equipment and have a drought/illness/something that impact their cash flow so they can't make the payments.
Read some good books. Anything by Heather Smith Thomas is VERY good. Her Storey's Guide to Raising Beef Cattle will really familiarize you with the ins and outs of raising animals.
Take some classes at your local extension agency.
http://www.cattleforum.com/entries/Wannabe-Farmers-Reading-List.html
Farming is not a get rich quick scheme. It takes lots of time to learn what you need to know. My family's been doing it for years and we're still learning stuff.