Some of the best ways to earn a lot, quickly, are to complete Offers, Surveys, and Tasks.
It requires a bit more time and effort than just clicking on the Daily Ads and ClixGrid, but the payout limit arrives much faster that way.
If you click daily (see the Daily Checklist in your account summary: www.clixsense.com/en/My_Account ) then you get bonuses for all activity afterwards.
I have managed, with a free account (and no active referrals), to maintain $8 - $10 per month for 3-4 months, which is quite decent considering how much more it could have been if I had a Premium Membership (access to more ClixGrid Clicks, more Ads, reduced viewing time per Ad, more Offers, more Surveys, more Tasks, higher referral earnings).
Since you have 19 referrals already, keep active daily, and add a nice message to your referrals to encourage and support them ( Sign In - ClixSense
) to help them want to keep active.
Just remember, ClixSense is meant to be "secondary income" (extra money), not your only income. When you do it in your free time, it is quite rewarding for little effort. Some people make plenty of money and are able to use ClixSense for their primary income source, but there are risks and costs involved in getting that far, and usually a lot of patience (building a large referral base takes time, continued effort, and often money / resources).
Happy Clicking and Good Luck!