In the 20 years I've been doing this job, I've probably interviewed, on average, four people a day, so that's maybe 20,000 people in total. I've attended maybe 1500 to 2000 press conferences and been on maybe 100 to 150 trips. Amid all the fun (the SAN-NAS wars, the LAN Manager versus NetWare duel and what have you) there have also been inevitable longeurs. Most of them have involved PowerPoint.

As the (largely innococent) victim of three or four thousand of these slideshows, some kind of compensation must be due in a just world. At a conservative estimate, 2500 hours must have been chalked off life's great innings: PowerPoint has stopped play for at least three months, four if you allow time for rest. I must have lost a day in dissolves and 'Any Questions?' closers alone. I have spent a week looking at clouds, factories, stick figures and other iconography of the modern presentation. Two hours that could have been spent in a pub, at football, the opera, child rearing, reading or, well, you know, has been lost to explanations of which precise part of California certain, largely forgotten software companies are located.

These are dark thoughts that summon the idea that the appropriate slide backdrop to the text should have been a  skull and ticking clock; a still life symbolising the transience of our measured hours on this earth. I write this with England having been bowled out for 102 in the Ashes and suddenly I couldn't care less about angled bats, hitting across the line, the Duke ball, an upright seam or a gully placing. This is my life we're talking about here -- or rather it was.

I can't get back those base-metal hours and alchemise them into gold but I do feel well qualified to instruct on the uses and abuses of PowerPoint, having also been on the other end of matters, keeping audiences spellbound through maybe 200 hours (call it a round week) of carefully argued, humour-salted instruction. So, for the sake of mankind, here are my 10 Do's and Don'ts of PowerPoint.

DO set rules about the session you're giving. The audience is allowed to leave electronic devices on for emergencies such as impending childbirth, divorce proceedings etc but not score updates or automated notifications of lagging performance in the Leicester sales area.

DON'T overrun. Tell them how long you're going to speak for, how many slides there will be then stick to these on pain of death.

DO keep your presentation down to 30 minutes. Few do so but nobody stays tuned in for longer. Thirty minutes of concentration has been embedded into the British psyche through formative years watching sitcoms and soap operas. And even some of those had advertising breaks.

DON'T be shy, embarrassed or worry. If it's dull or weak, people won't listen but that's because you haven't prepared well or you have the wrong audience. Beyond that, nobody cares so what's the worst that could happen. Thing of something awful that's happened to you and laugh at how far away it is from standing up with a wireless mouse. Then go get 'em, tiger.

DO ignore professional PowerPoint types that will lock you in training rooms explaining how to bend shapes and import things that should never, ever be imported. It's waste of time, like completing crosswords or playing Su Doku. Simplicity is elegance and you've already had to move things around to squeeze in that stupid ACME Corp. logo. By all means use the wonderful SlideShare to help you prepare, donate and steal ideas.

DO ask questions. Face it, that stellar list provided by the marketing department will have been diluted somewhat by the time you're on the podium. The CEO of General Electric has been replaced by his PA. The BBC couldn't get there but the Movies For men channel have taken their place. You need to figure out who these people are and engage them. Get them on the edges of their seats by asking them questions so they can't doze off, even if they'd like to. They can always leave if they don't like it and if they're not interested in sharing their experience and views they shouldn't be there. And by all means crack jokes -- life's too short and a sympathetic ripple is better than nothing.

DON'T worry too much about graphics if you're speaking to an audience rather than just sending files out. Everybody will tell you the importance of images over text but Telly Savalas said a picture paints a thousand words -- did you believe him then? Lincoln didn't have a war artist alongide him and a laser pointer when he gave the Gettysburg address. If your words or ideas are powerful enough, sheer force of argument and personality is much more impressive.

DO feel free to lean on text on slides. Everybody says this is wrong but then data* suggests that the average audience can only recall the PowerPoint for three minutes and 23 seconds after it is finished so the text will act as a memory aid or summary.

DON'T, on the other hand, just read out what's on the slides. That's just a waste. At least talk before showing summary points. Oh, and don't let them have printouts beacuse you know what happens then.

DO put your contact details on the end slide. The delegates you thought were bored loved it; they just didn't want say it in front of others. 

PowerPoint is a wonderful software program. It has been used to pitch many of the modern world's great inventions. It is a portable electronic illustration of the wonders of the human mind but like many powerful tools (he said sententiously) it can also be used for ill. So love it and don't waste your precious time or the time of others. Always remember: it's later than you think. 

* or personal experience at least