In order to get your message across, you must speak as clearly as possible. Many speakers, particularly when they are nervous, tend to speak more quickly, making them harder to understand. You need to make a real effort to speak more slowly - in fact, it is almost impossible to speak too slowly. The point is to get your message across, not finish as quickly as possible.
Clarity and diction are important too. Some people worry about their accents when they are speaking. These days, this is not a problem, since all types of accent are now commonly heard. However, you do need to be aware of any local dialect words that may confuse a wider audience. A friend of mine, top professional speaker Kenny Harris, tells of the unusual way that certain Scottish folk sometimes respond. "If you ask a Glaswegian a question, and he says 'Aye, right', he means 'No'" says Kenny. "They're probably the only people who can put two positives together to make a negative". All over the world, there are words and phrases that can puzzle your audience. As ever, the best advice is to keep it simple
Using pauses is one of the most effective ways to improve communication. Not only does it help you to gather your thoughts, but it also helps your audience to digest and understand what you have said. It can be very difficult to get used to using pauses, since we all have set speaking patterns. It is well worth the effort, though. You can practice pausing by counting silently to three at the end of each phrase or sentence. The first time you try, it will seem like a lifetime, but persist until you are used to it. You will find it much easier to do if you talk to someone else, as they will be able to give you the feedback that it sounds just fine.
One of the best ways to improve your clarity is to change the pitch of your voice. We have all hear speakers who deliver in a monotone, causing most of their audience to doze off. You should aim at raising and lowering the pitch of your voice occasionally to maintain interest. Overall, try to lower your voice more than raising it, since this is easier on the ear of your listeners. So - just speak slowly and clearly. Simple, Eh?