The downline builder helps you get a few referrals without having to do any work for them. You sign up under the last person listed in the builder, then the next few people that come along to sign up for that program will do the same and end up in your downline. (Read the rules posted at the top of that forum to find out exactly how it works - I've never used it, so I don't want to give you incorrect information.)
Unless you get lucky, you'll probably just wind up with one referral on each level by using the downline builder. And if my own experience is anything to go by (and from what I read around here, it's pretty typical), most referrals don't click much no matter where you get them from. That means you usually need to get a lot of referrals in order to end up with the few that will earn anything for you.
As for tips for getting referrals - well, I know that what I do doesn't work very well. I'm not particularly interested in getting referrals, so I don't try very hard, and therefore, don't get many.
If you want lots of referrals you have to advertise. A lot. Try to make your ads stand out and get people's attention. Keep track of and analyze your ad results. Make changes and see if you do any better. Cross you fingers. And your toes. Oh, what the heck - cross your eyes, too. It can't hurt.