Any traveler who's become all too accustomed to the cramped and stuffy confines of economy class air travel couldn't be blamed for occasionally fantasizing about what unknown pleasures might lie in wait for those who head the other way - towards first class on boarding. It's just possible that with a bit of luck and some classy blagging you could find out.

Flight upgrades are a topic shrouded in mystery. The airlines are unlikely to make whatever policies they might have public. The logic being I suppose that if passengers come see it as a realistic possibility they'll be less than thrilled when it turns out not to be possible ? not good PR. Indeed, before I go any further I should suggest that this remains a working assumption ? upgrades aren't something most of us should come to expect but, hey, it can't hurt to give it a try. Familiarise yourself with the following tips and who knows?

? What every prospective upgrade blagger should be aiming for is an SFU stamp on their boarding pass. This stands for Suitable For Upgrade so if you see NSFU (Not Suitable For Upgrade) forget it, the games up.

? So, how does one go about getting the SFU stamp of approval? Well, first of all make yourself presentable. This basically means dress to impress and let's face it nobody's going to be impressed if you roll up looking like you've just spent the night sleeping rough. The logic here is obvious - dress like a well-heeled businessperson and you won't look out of place in business class.

? Travel alone and you're bound to improve your chances over anyone who turns up with their whole family in tow. Essentially the lone traveler will always be easier to accommodate in those elusive first class seats than a large party of people. The big exception to this rule is honeymooning couples, if you genuinely have just got married take along your marriage certificate or at least let the staff know - even if you don't get an upgrade a complementary bottle of champagne is a real possibility.

? Who you are can make a big difference and I don't just mean the usual Celebrity / VIP candidates. It's actually well reported that those with a Dr or Rev title on their passport are often given very accommodating treatment. Perhaps airlines imagine they'll be more responsible when it comes to the complementary champagne.

? Logically it makes sense that the more first class seats there are going, the better chance you've got of nabbing one. Check out which of the viable airlines for your journey has the largest fist class area by looking on their websites.

? On a similar note, avoid travel times when business class is likely to be full. So the weekend and times outside of normal working hours are a good idea. However much of a drag getting an early morning flight can be, this might just be the best opportunity.

? A bit of subtlety could well pay dividends ? if other passengers hear you've successfully blagged an upgrade they might expect the same treatment so check-in staff probably won't risk it. A bit of subtlety could go a long way.