Have you started him in pull ups yet? That was my first step .... and taking him to potty, whether he needed to go or not, about every 2 hours. He seemed to become more aware of the wet vs. dry feelings in a couple months. I think the independence he felt wearing the pull ups really helped alot because he was excited to be able to do it by himself - which was "fun". And, within a year, he was completely potty trained. I think you're timing good to start now. Good luck
My son with DS is 5 years old and not yet potty trained but we started off by letting him go outside this summer. He thought that was cool. And really easy for me as we were outside all the time. It helped him know what it was expected without dealing with alot of wet clothes. Pull-ups give him a false sense of security and he will use them like his diapers. I also had my husband show him how to use the potty like daddy. Austin loves to do whatever his daddy does. Just about every time we take him, he goes. We are not fully potty trained but he is very aware of what is expected of him. If I took him more often I think he would be trained by now. He is in preschool and they take him but probably not quite as often as needed. I am going to do my best this summer to completely train him.
My 6.5 year old is still not fully potty trained. I'm not even sure if I should say he's partially trained! He will teetee in his pants if we don't take him to the potty. He rarely asked to go teetee on his own. Thankfully, most times he will poop on the potty. But he still has a lot of accidents and at night wears the night time diapers. It's one of those milestones I can't wait to accomplish, but like all of his milestones, I am so excited for his accomplishments when he crosses one! Here's hoping he won't be in diapers in high school!
It is probably too early at age 4 to start with the potty training and it will only give you both more frustration than it is worth at this time. My son was fully trained at 6 years old with the average being 7 years old. I mean totally toilet trained - going on his own without accidents and without be put on the toilet or made to go on some schedule. We tried at earlier times but quit when it was going nowhere. I can say that cloth training pants helped much more than the padded throw away trainers and once he was ready - it just happened. We were on a camping trip and had a porti-potti in the pop-up and he just crawled on and "went" and that was it. We tried all the silly stuff like rewarding with M & Ms, flashing the lights in the bathroom like he won a contest or something - does seem silly now. For us at that time, being toilet trained seemed like it would give him the golden entry key to all the programs not allowing kids that were not toilet trained but they kept raising the bar so that basically it was always some new thing we had to conquer. Keep in mind that reaching the milestones has nothing to do with the eventual functioning level of your child.
Summer time is the best time to start potty training. I have a 7 yr old that has been potty trained since age of 4. It all started with him having a BM in his swim suit and I took it off, well then his dad took him and let him pee on the truck tires. That is how it all started. Find something that is fun and that he thinks is neat. I spent the rest of the summer out side as long as I could stand the heat and he ran around with no pants on. Any time he peed we praised him, and he learned to sit on his potty out side to have a BM. You just need to find what excites your child and go with it. You also need to be able to devote as much time as possible to what you are trying to do. Don't get frustrated, they see it and then associate it with getting in trouble. Be excited with everything. Hope this helps