There are several key points to consider that can really help improve your public speaking skills.
Do your homework so that you’re well informed on the speech or presentation that you will be giving. Compare it to the opening paragraph of a book and try to start it with something interesting to immediately intrigue your audience. Organize your thoughts with an order of topics. You could use cue cards to help you remember, but avoid reading them word for word.
“Practice makes perfect” goes the phrase, and it’s certainly true of public speaking. Take as many opportunities as you can to practise out loud either on your own or in front of others. Use the resources that you are intending to use when you deliver it for real. Tweak it if necessary to make it flow.
Taking a deep breath can help you to control the tone, pitch and volume of your voice. If you stop to take a breath you will ensure that you are not rushing through the presentation, you will not be speaking too fast and people will be able to hear what you are saying.
Engage with your audience, smile and use eye contact. Watch out for communication from the audience. Smiles and nodding are positive signs. Fidgeting or confused looks may seem that you are changing what you are doing. Avoid using fillers like "erm" and "err". Be aware of body language. In general you should adopt a relaxed, upright stance with your hands by your sides unless you are gesturing to emphasize a point.
Visualizing delivering a successful speech will help give you confidence. If you can, get a film of your presentation so that you can learn from your performance to improve in the future.