An important part of a talk is to introduce your topic and subfield. You need to convince them why what you’ve done is important. Even specialised conferences have broad audiences who may not be familiar with your techniques or application. Even if they are your interpretation of concepts and your assumptions should be stated clearly since people from different places may not follow the same conventions. You will need to explain them in more detail than you would to people familiar with your progress. No matter the conference, you should not assume that they’re already familiar with your topic: it’s your responsibility to explain it (of course can adjust your content to your audience).
You need to get them interested in your topic, tell them why it’s important, why you took the approach you did, and what was challenging or novel about it. A clear structure is essential for any talk. You need to allow time for this.
Considering this, 20 minutes is not a long time slot. You should focus on one or two key results and explain them well. We all do far more work than ends up in our papers or talks and it’s understandable that you want to show your work. However, it’s more important to communicate the key findings well. Especially, if you’re early in your career, you should aim to demonstrate that you know what you’re doing and have mastered particular techniques. If they’re from a related field, they probably have an overview of your area already so a key example to demonstrate why they should care about your area is going to be more interesting for them than yet another overview.
If you race through everything you’ve done, you won’t stand out and know one will understand what you’re talking about or why it’s important. You can of course mention the other research directions that you are working on to put it into context of what you’ve done and what you’re doing next but you need to focus on something. Every PhD student or postdoc has a mountain of data. What your future employers and collaborators are looking for is someone that understands what they’re doing and can communicate it well.
It’s also considerate to finish your talk on time. Allow plenty of time for questions and discussion afterwards. If you go overtime, you will have to rush and this will not help your nerves. You’ll be very unpopular if you cut into the time of the person after you and delay everyone’s coffee break. Keeping a conference on time is difficult and adhering to the schedule is important. It’s a lot easier to keep to time if you set achievable goals of a few key points. You need to identify the most important findings to present or emphasise: this is a skill you should develop in a career as an academic researcher.
Help yourself and your audience by preparing well. There’s only so much that people can remember for take home messages from a full day of talks anyway. Think about what you want them most to understand from it. If they want to know more, they can discuss it with you after your talk or read your papers. The purpose of a talk is really to introduce yourself and give people context and background.