Hi Elia,
I find it helps to have your presentation done in plenty of time and go over it a few times - practice with someone else if you can.
Other tips: remember to look at the audience, keep it natural (pretend you are talking to people you know), relax and enjoy it!! People will be much more receptive if they realise you have a passion for the subject you are talking about. Try and make a couple of light-hearted comments to again keep it relaxed and SMILE!!
Once you have presented a first time it will feel so much easier second time round! I'm now at the stage where I actually enjoy presenting :-)
Leanne x