Is there a secret to getting a tight seal when putting solderless fittings on 1/2 inch flexible copper?

I recently changed my chiller to use a bigger pump that I already had. It is similar to, I think Greg and Jeffs, that I've seen at club brew days. Before it was a fountain pump and all the connections were done with hose clamps. When that pump broke, I had to make some changes... Modified, it now uses hose connectors and brass quick disconnects for convenince.

When I went to use it Saturday, I started out with the water hose to get the heat down quickly. But when I turned the water on the cold side (in) connectors was leaking so bad I had to wrap it in a washcloth to prevent it spraying into the pot. I decided not to move to the pump because I didn't want to touch the connector. It worked well enough, better than and ice bath, once I got that bit soreted out.

I also realized how inefficient this coil is because of the mistakes I made when I bent the copper. This one was made for my origional brew pot, ~4 gallons. With my 9 gallon pot two full coils are above the wort. might be time to make a new one.

Welcome any advice on the subject.