Hi! Make it fun and rewarding. A fun kids potty seat and some convenient games will add the fun element. Pretend to make baby drive a car. Also, you can get some underpants that have fun cartoons on them.

make the baby aware, say he is a big boy now n should not use diaper always,etc etc. Give him some time, it's just master of time he l learn. Take him to washroom regularly at home. hide diapers for couple of days if possible :p say u r yet to buy them from store.

this is your best tool

http://www.dailymontessori.com/self-development/toilet-learning-vs-toilet-training/

omg! dat sure is a big pblm...u should have started potty training the baby as early as 7 months...I'm training my baby now.its difficult but still continuing as she has not started sitting all by herself. You can show examples of other children and tell him that its a shame to continue wearing diapers as he's grown up.you know children love growing up and telling smart boy etc....tell him that grown ups don't need diapers or smart boys don't need poop or pee on diapers,if anybody knows this its gonna b a shame etc....your child might be able to withdraw this habit if u continue saying this.