Make sure that you are over your breakup. If you are still crying yourself to sleep or want to get back with your ex, then you probably aren't ready. Some people will be ready to move on after a few weeks, others will take several months or years. It is all about making sure that you are okay that your relationship is over and are ready to start dating again.
Learn from your past relationship. What did you do to cause the breakup? If you could go back to the day you and your ex met, would you do anything differently? Learning from mistakes will make sure that you choose a new partner who will be better for you.
Get out of the house and meet people. Ball games, social events, and church organizations are great places to meet people. Practice talking and flirting with all kinds of people to figure out what you like and what you don't like. If you haven't been single for a long time, your preferences might have changed, so take time to talk to all types of people.
Go slow when you start dating again. Instead of trying to find the love of your life or a new boyfriend/girlfriend, spend time trying to date and get used to it. Don't rush into the physical part of a relationship right away, instead take a little longer than you would have in the past to make sure that you are happy with your new partner, not just trying to find a new boyfriend.
Understand that there will most likely be heartache and when you start dating again. But, if you are willing to take that risk, you may fall in love again and be incredibly happy.