Any advice for someone starting to play Pokemon Go soon?

I started playing Pokemon Go when it first came out, but my phone wasn't really up for it so I had to stop. I'm looking to get a new phone soon and thought I might start again. I'm sure there have been some pretty big changes since then so anything you can tell me or help me with would be greatly appreciated. I don't think any of my friends play, so any advice about which team to join or which Pokemon to start with would also be awesome. Just any hints, tips, or advice at all for anyone starting to play Pokemon Go is what I'm looking for. Thanks in advance