When you're first learning about public speaking, your mind is overwhelmed with new information. As I mentioned in this post, your brain is going a mile a minute with the following thoughts:
What did I just say?
Look at the left side of the room.
It's hot in here.
Am I pacing? Stop pacing.
Stop fiddling with the remote.
What comes next? What comes after that?
Push the button for the next slide.
I'm running behind. Should my activity take five minutes or three?
That person's not paying attention. How do I get her attention?
It's cold in here.
Uh oh, crutch phrase.
I need a drink of water.
Look at the right side of the room.
What was the name of the guy who asked that question before?
Why did I wear these shoes?
Was that clear? Maybe I should explain it again.
Good luck trying to remember your content with all of that going on.
Don't be so hard on yourself. When you're just starting out, pick one new skill to practice each time you speak, and focus only on that.
If eye contact is difficult for you, work on that for the next few presentations. If your voice projection is weak, make that your focus for a while. If stories and analogies are lacking, just practice those for a while.
Nobody is born with all the skills in place to be a successful and engaging speaker. It takes a lot of practice and a lot of real-world experience. It takes a while to be able to put all the pieces together in one presentation.
And, for that matter, even the pros continue to practice their skills and keep working to improve every time they speak. We're never done learning and growing.
So take it easy on yourself. Keep your expectations realistic about what you can accomplish in each presentation. Focus on one skill or strategy each time. When you feel more comfortable, start adding to your toolbox. Before you know it, your body and mind will be working together unconsciously and automatically to put all the pieces together.
Take your time. It's a process.