The red flags he's talking about are in the early stages of the relationship... where you probably aren't exclusive to just the one girl.
So, if she starts to flake a bit, you just pull back a little further. Go out with another girl for a night or two, or just get really busy. (you should be busy, anyways)
In the context of you two being in a more serious relationship, you really need to start examining your behaviour. If you are being too clingy and needy (you should never be any of these qualities) she will start to lose interest and you will see red flags. Again, just withdraw your attention, so that she knows she doesn't have you wrapped around her little finger.
That's a pretty generic respeonse but I hope you see what I'm getting at.
What do you define as red flags?
