As far as I know there aren’t any fixed rules about how to use bullet points. So this is how I normally use them.
I like to introduce lists with a colon (that’s this punctuation mark here :).

I don’t use full-stops when I write a list of items.

Please bring with you:

  • pens and paper
  • dictionaries
  • a pair of scissors
If my lists are made up of full sentences, I start each with a capital letter and end each with a full-stop.

Things to do before you write an email:
  • Plan what you want to say.
  • Make some notes.
  • Think about your subject line, your salutation and how you want to sign off. 

If my lists carry on from the introductory text, I use lower case (small letters) for the first letter in each bullet point and only add a full-stop to the very last sentence.

Before you write an email, remember to:

  • plan what you want to say
  • make some notes
  • think about your subject line, your salutation and how you want to sign off.