I had this problem as well and can offer you what has worked well for me: (Would love other's input.)
1. Place most important piece at the top. Answer the following question to your audience: What is the purpose of this email and how does it apply to me?
2. Bulleted or numbered lists are ideal for multiple questions/points. It visually divides, gives you ability to order most to least important and also allows someone an easy way to respond inline to each question.
3. Iterate on your first revision with goal of reducing length and maintaining intention. This takes practice and forces you to ask do I really need this line of text.
4. If you distribute to a large list, identify at the top the scope so those it doesn't apply to can discard.
5. If you are emailing a group and you need replies or action items for different people call this out. You can do this by calling each name out: @Joe - Can you help identify x? @Jane - Can you follow up with so and so? etc. This way their name is attached to it.