My son is 16 months & we just bought a potty today (he's carry round as I type LOL). I find that every time he is naked he will stop look down then take a step back just before he goes so it seems as though he knows when he's about to wee. He will also bring me a new nappy if there's one in his reach whenever he wants it changed.

Sorry I'm not much help, but just wanted to say it looks like we're going down the TT path too very soon *eep*