So many good tips here. There's many things to focus on, but I went from someone who had to memorize everything to being a recognised speaker and now coaching fellow students onto winning oral prizes. I still feel the adrenaline rush even just to ask a speaker a question but I learnt to admit it's ok. Here's a few main points. Basically preparation is everything. The more you take care of off stage the less you need to worry/stress about on stage.

1. Plan your slides well- put in key points, don't use them primarily as your speech prompts, but rather a visual aid to what you're saying. That said, try to anchor your thoughts and main points on there so you can recall. Don't clutter slides, less is more. Make sure things make sense, make sure diagrams are easy to read.
   
2. Don't give the talk from your PoV (ie I was asked to present so here's a bunch of stuff I worked on blah blah). 90% of speakers do and it's dry, boring, often emphasised on the wrong kind of information and ultimately hard to understand/remember. Write it from the audience's PoV- who are they? What do they care about? What story can I make of my topic/research that will connect with them for it to be interesting and easy to understand? How do I keep them engaged and walk away with the key things I want to share about?
3. The important thing in keeping the flow of the talk is the transition between points and slides. They are often more important to commit to memory than the content itself. Linkage makes all the difference in helping your audience grasp the message. Devote special attention on how you link topics/slides and practice those
4. On practicing- do it in front of the comp, with timer and everything. You will hate how you sound and nothing is coherent. That's ok. You're doing it to work out where the trouble spots are. Take notes as you go, record if you want. Then use a projector. Find a friend and practice, then a small audience/ group meeting. Get feedback. Don't expect your supervisor to get people to help you, use your own initiative and ask people to listen and return the favor.
5. Visualise yourself giving the presentation. Check out the room/lectern, get familiar with the setting. Stand at the stage and soak it in. Later, imagine yourself standing there giving a great presentation, you remembered everything, you spoke clearly calmly and confidently, you aced the questions. Notice how calm you are, how you're breathing normally and projecting well. Develop your style and tone.
6. On stage- (already said here but worth reiterating) Fake it till you make it. You're a nervous wreck, your heart is palpating, it's ok, they can't really see it. Remember the audience WANT you to give a good talk and succeed. They rather hear an interesting coherent talk, so give it to them. Keep your energy levels up, don't rush. If you do go overtime cut straight to conclusion, don't drag on detail as nobody will listen by then. The interested will find you later.
7. Take every opportunity to practice- give presentations at small research meetings, do a journal club, enter competitions. Practice makes practice. Get a mentor/coach, someone whose style you like and ask for feedback. Don't be afraid, don't be too self critical, keep going. Pick yourself up if you do have a disaster presentation, happens even to the best of us. It honestly isn't easier for everyone else, we are all faking it.
8. You'll always feel nervous, tell yourself that's ok. Eventually you'll do enough talks to know the feeling well enough and to perform in spite of it.