Apart from points earned through flying itself, many of us rack up additional frequent flyer points through credit cards and supermarket reward schemes. If that doesn't make your total rise up fast enough, there are weirder options on offer.
Australian Business Traveller outlines some real-world examples of extreme schemes used to earn points, including a US resident who purchased 12,000 puddings as part of a points-earning promotion; earning points for gambling advances and then making that money back on low-risk bets; buying money orders from Walmart to earn points; and paying massive wholesale ISP bills in Telstra shops with a credit card. Hit the article for the full details of each scheme.
While the accounts are amusing, very few of these tactics would readily translate into long-term, risk-free strategies anyone could use. Australian airlines don't generally offer generous points accrual schemes on supermarket goods; using gambling funds relies on coming up with good winning bet options and might make life interesting at tax time if you did it too often and came to the notice of the ATO; and the Walmart loophole got closed fairly quickly. Paying bills on the credit card seems the easiest bet, but check to see if there's a ceiling on what you're allowed to earn through any one card.
World's weirdest tricks to earn frequent flyer points [Australian Business Traveller]