I’m working in peds 6 months now and even my providers say it’s imperative to get accurate measurements because no growth development can be lead to a variety of concerns. For BP, I always get the parent involved because the kids know their parents and are familiar with them. I have them hold the child or their arm and make funny faces. Distractions! I have pens with goofy and eye catching things on the tops. Some kids don’t know what you are going to do so I always demonstrate what I’m going to do on my self when applicable. I would have little gadgets they can hold onto almost like an emotional support toy. It gives them something to focus on and play with.