There are many different aspects to wearing diapers that need consideration, and everyone's experience of them is unique. From the sounds of it, you're a little and would like to try wearing diapers as a means to enhance your experience of regression. This is in stark contrast to, say, a diaper lover who isn't really into regression, but simply the physical sensations of wearing a maybe using a diaper.
My advice to you if you go ahead and try wearing; above all else, make sure you have sufficient time, space and privacy. If you're rushing the process, or are constantly worried about being caught by others etc, this can easily lead to a bad first impression.
Also, do a bit of planning ahead for the 'mechanics' or logistics of the process. Things like: How are you going to acquire the diapers? Where are you going to store them? Where and how are you going to put one on? How are you going to dispose of them afterwards? You'll save yourself a lot of stress if you sort these things out first.
If the idea of using the diaper for it's intended purpose appeals to you, then there are more things to take into consideration. A used diaper will have to be disposed of in a certain way, and you'll need a way to clean yourself afterwards. And in terms of actually using them, the main advice I'd give is not to force it. Allow your body to do what is needed only when it is ready. I myself drink a lot of water in the lead up to wearing.
For me personally, I started making myself makeshift nappies out of plastic bags etc as an early teen, but it was only in my late teens that I was able to acquire actual adult-sized diapers for the first time. I've been wearing then sporadically ever since, and in the past year or so I've started to try the products especially designed for ABDLs. If you can get hold of the more premium products, they're worth it.