The key to potty-training success is starting only when your son is truly able to do so. While some children can start as young as 18 months, others may not be prepared to learn until well into their fourth year. As you may already have discovered, boys tend to stay in nappies longer than girls, and second (or subsequent) children often learn faster than firstborns
Toddlers learn by imitation, and watching you go to the loo is a natural first step. This is where having a readily available male role model is key. If he wants to, let your son follow Dad, an uncle, or a good family friend to the bathroom to watch him pee
Most experts advise buying a potty, which your toddler can claim as his own and which will also feel more secure to him than a full-sized toilet. (Many toddlers fear falling into the toilet, and their anxiety can interfere with potty training.) If you prefer to buy an adapter, or training, seat to fit on top of your toilet seat, make sure it feels comfy and secure and attaches firmly.
Get your son focused on the benefits of being potty-trained by taking him on a special errand: buying underwear. Let him know that he gets to choose whatever kind he wants (superhero pants or boxers, or ones emblazoned with favourite TV characters are always popular). Talk up the outing in advance so he gets excited about being old enough to use the potty and wear 'real' underwear just like his dad's or older brother's.
Nothing helps your toddler suss out when he needs to go better than letting him spend some time bottomless. Put the potty in an accessible place while he plays, and encourage him to sit on it now and again. Of course, if he's going to play naked, you'll have to steel yourself not to get upset about the occasional puddle (putting plastic over your carpet can help with this
By the time your child's ready to say goodbye to nappies altogether, he's achieved a lot. Acknowledge this and reinforce his pride in his achievement by letting him give away leftover nappies to a family with younger kids or send them away with the nappy delivery service one last time