One should be enough, but only if you really can't find energy for more.

But what's more important is how you do them. You have to put emotions into RCs. Each time you have to believe you are dreaming and that the RC will work. It has to be "omg, I'm dreaming" and then do RC and believe it will work. So when you are in a dream, you don't just do RC automatically without realizing you are dreaming. If you do it right, you will get that OMG feeling in a dream too and it will get you lucid.

Find some fun RCs to do.

Collection of techniques for DILD - awareness+RC+mantra