I have yet to meet a parent who has had an easy time potty-training their child. The truth is, there is no specific time and place to approach the process. Of course, there are plenty of books on the topic and several different proposed approaches. Yet, the best approach needs to depend on your child, their development, their level of interest, their social and emotional environment, and other compounding stressors.
While working in early childhood education and building partnerships with parents for nearly two decades, I have found a few developmental markers to be good determinants for knowing when to best approach potty-training:
Is the child physically capable? Does the child have an established sense of autonomy and self-help skills? Is the child talking about using the toilet? Do they let you know when they've soiled their diaper and need a change? Can they communicate when they have gone pee and poo in their diaper? Is there enough time and energy in your day to allow for a lot of error and messy mistakes for at least two weeks? Are you willing to commit to the process no matter how challenging it gets?
Once those guiding questions are answered, then we can begin to consider a plan! I would first encourage you to flood your child’s library with books about the human body, potty, toilet use etc. Perhaps purchase a small play-toilet and dolls and begin to "broadcast" or reenact how you and other members of your household go pee and poo in the toilet. I would consider planning to begin training during a school break or extended period when your parenting partners can commit to a lot of clean-up and messy, yet very normal, challenges throughout the day. I would plan to transition straight into underwear. A child is likely to become confused by the sensory sensation of a pull-up or diaper for certain periods of the day during training and they may choose to soil their pull-up or diaper because their muscle memory finds these physical comforts familiar. You could consider the first week of training naked in the house and have the toilet available to your child at all times. The goal is to remove the physical and sensorial comfort of a diaper or pull-up and replace it with the emotional and social comfort of your support, non-judgment, and leadership. You can plan to have several extra pairs of clothes at school for them and attempt a toilet try every 45 minutes to an hour, which is essentially built into your child’s daily schedules and transitions at school.
It is important to prepare for and expect a lot of mistakes, some tears, and a lot of messy accidents. If we can approach these moments as a natural part of it all, it removes the shame, fear, and stress for the child and guilt as a parent. If your kiddo has an accident, I would not address it with them. I would very casually acknowledge that it's time to change their clothes and that accidents can happen sometimes. I would conversely make a really big deal every time your child doesn't have an accident and use some intrinsically motivated prompts such as “How does it feel to be able to use the bathroom all by yourself?”, “How does your body feel in clean underwear?”, “I feel confident every time I use the bathroom.”
Lastly, it is important not to reward successful bathroom use with stickers, toys, or extrinsic motivators. Since this is a really big challenge for any child to try and champion, stickers and toys add a lot of stress. It builds extrinsic reward behavior and can negatively impact your relationship with your child. A good way to think about it is to think about all the other things your child does throughout his day that he just learned internally as something he had to do...For example, we don't reward children for getting out of bed, brushing their teeth, or going on a walk. They just do it because they've learned it's a part of being a growing child. Similarly, children can begin to learn that going to the bathroom is a part of growing as a child, not something they have to earn, be rewarded for, shameful about, or struggle to achieve. It's just a part of the day.
So approach it with ease, casual energy, open-mindedness, and commitment. If you can commit to it, no matter how messy it gets, your child will trust the process and you as their supportive and loving leader.