What I did with my 3 year old (she was 3 on 2nd July) was just take her clothes off and let her run around the house naked and then if she did a pee, she would notice and eventually she started sitting on a potty of her own accord, that I just placed in the room without mentioning it to her and just let her go to it if she wanted.
She was trained during the day at 20 months old and trained overnight from about 2 and a half.
After all, at that tiny age they don't need clothes, especially if it's warm and it's the quickest way of teaching them.
