Here are some more tips based on some experiences gained this year from giving (lots of) presentations. I’ve also included a few good suggestions that have been suggested by friends and colleagues (they know who they are and I am happy to acknowledge them by name if they don’t mind being publicized here).

1. Don’t give people negative information about you or your material. They will only use this against you in feedback. If you’re not happy with the material you are delivering or its content you really should not be presenting it however at times we all have to deliver a presentation with dodgy slides or containing messages we may not agree with or fully understand. Try and spend time up front pulling out the key messages and deliver those rather than try to justify or apologise for poor slideware. Spending time practising is key.
2. Check out the room you will be presenting in ahead of time and if it is big or has poor acoustics which will make it difficult to project your voice make sure you get a microphone (or be prepared to shout all through the presentation).
3. Be aware of an audiences mood. Glazed eyes, playing with smartphones and doodling means you have lost them. Re-engage by throwing a question or two at the audience but better still follow 4 below.
4. In the excellent book Brain Rules its author, John Medina, says that audiences tend to “check out” after 10 minutes and it is therefore important to pepper your presentation with attention grabbing events. These can be anecdotes, personal stories, jokes (if they are relevant to the presentation) or maybe playing a short video. Medina even recommends designing your presentation in 10 minute chunks where the end of each 10 minutes has one of these attention grabbing events.
5. Buy yourself a good quality wireless presenter (AKA a ‘clicker’). It gives you freedom to move around and blank the screen to avoid distractions during discussions. I have one of these which has served me well (always carry spare batteries though). Having a clicker more easily allows you to do number 6 as well.
6. Don’t stand still and just talk at the audience. If you, can walk around and engage with people (use eye contact when speaking). If you have any influence over the layout of the room make sure tables and chairs are laid out in such a way you can move in between them. Even if you are on a stage you can still move around (watch any Steve Jobs presentation to see what he does). Also use your pitch and volume to emphasis the key points of the presentation.
7. Don’t be afraid to say you don’t know when asked a question. Unless you are an extremely good bluffer you will be rumbled and lose all credibility. Better is to admit you don’t know the answer and offer to follow up afterwards (which you should do if you say you will of course).

See also here for tips on creating technical presentations and here for what not to say when presenting.