Before my life as a loan officer, I was fairly introverted and didn't include myself in most conversations that took place in public settings.  Being a loan officer forced me to alter who I was or at least change some characteristics of myself.  I joined a club that helps with giving speeches, perhaps you have heard of them, they're called Toastmasters. 

Here are some tips that have helped me and they may help you as well:

• Practice giving your speech within a defined time period
• Arrive early to your destination, this will help calm your nerves
• Practice your speech out-loud
• Speak at a level that is appropiate for the room you are in
• Conceal your notes so they are not immediately in front of you, this way you cannot draw attention to them
• Do your best to not say "ah" or "umm" while giving your speech
• Do your best to remove any physical quirks you may have, ie tapping your finger on the table, spinning your pen

Joining Toastmasters has helped me in other ways as well.  I am much more confident with myself.  I appear to have undergone an "extreme makeover", at least according to some of the people who knew me years ago.  I owe most of this praise to Toastmasters.  If you find yourself stumbling in public speaking engagements or with clients, take some time to see if there are any Toastmaster Clubs in your area.  The dues are inexpensive and you will enlarge your sphere of influence while gaining some confidence that will help you in many other areas.

The following (in bold) was taken directly from the Toastmasters website...and I couldn't agree more