How do I work with my dream signs?

I've read that I have to identify my dreams signs from my journal.

Once I've done this what do I do with them? Should I meditate on them? Turn them into a pre-sleep mantra maybe?

You should tell yourself that whenever you see one of them you have to question your reality. "Whenever I see a cat, I will RC" if a cat is your Dream Sign. Mantras before bed works, but also during the day. Preferably as much as possible to make sure you remember to RC when you see one.

Thanks.

The only dream sign I've identified so far is a girl I once knew so I guess I won't be able to RC that sign. I'm patient though and I'm sure some more will turn up that I can act upon

You shouldn't only rely on dream signs. RC whenever you remember, because if you make it too much of an "automatic thing" that you do when you see a dream sign, you'll do the RCs in the dream without realizing it. Awareness is key.