Okay, let's see how those on the board really stack up in terms of secrets and strategies for earning points and miles. Everyone post their best tip or tips to earn extra mileage. We're looking for advanced mileage strategy here--not something as simple as "charge all expenses in the hotel to your room, so you then maximize the hotel's program points on check out."
I'll start. We REALLY maximize the total dollars we can charge to our affinity credit card. My mother in law lives in town near us, and anytime she has a particularly big expenditure, we of course volunteer to charge her expense on our NationsBank Dividend Miles Platinum card (1.2 miles per dollar). She then makes out the check to us, instead of to the store or merchant. For example, last year she had to replace her Central Heat/AC system. $4000 dollars, so 4800 miles right to our US Air FF account.
Okay, I've started. Let's hear the strategies.

1) Just to follow up on Djlawman charging big amounts to the affinity card, don't forget about charging college/tution either, some colleges won't accept that payment method, and some will. For me, med school at 25,000 a year, adds up the miles nicely.

2) Make all ticket reservations through the airline's respective web site, to get the extra miles, even if you're have to call over the phone to make changes, get better seat assignments, or want to use an upgrade cert. I've always gotten miles from AA doing this, regardless of any changes I subsequently made.

I charge everything on my affinity card (but all it gets me is miles, not status miles). I heard about a guy who had millions of miles because he filled his company's postal machine using his affinity card (now that would be a dream if you were running a mail order operation!)

You'll find plenty of good tips in the latest InsideFlyer, although they are targeted more towards the novice/intermediary FF.

I was once told (but could not verify) thet there are still gambling cruise ships that will allow you to charge chips to you room, but let you cash your winnings in in cash. The story was someone charged $10k in chips to his room, didn't gamble, paid the room charges on credit card, cashed in the chips, and sent a bank check to the credit card company. An easy 10K miles.

But as I said, it was second hand, and I neither verified it nor tried anything similar.

Dave

FF-flyers Guerilla-tip #NNN ("how to beat the system"): One of my friends says:

"Buy full fare (one year valid, exchangable, returnable) flight-tickets with a (mileage-program) credit-card, then just AFTER cashing in all your miles and just BEFORE giving up that credit-card (best Diners and/or American Express), return the tickets and let them be fully credited to your credit-card-account."

Rudi--now that's a really interesting strategy. However, I don't think it works. If you get the refund of the ticket, it is applied as a credit on your account. (Of course, if you cancel the account, they'd probably give you a refund check, but who wants to keep changing credit cards, just to get an extra 1000 or 2000 miles from this trick?)
BTW, THANKS for the great airport guide and the swiss chocolates from the December award. My wife and I have both appreciated the chocolates already, which just arrived today.

Royal Carribean does indeed let you charge chips to your room (which you pay with your affinity card) and take your winnings in cash. If you have winnings. Hee hee hee.

Here's a couple basic tips...

a) The majority of my flights are from St. Louis to destinations in the Northeastern US. Especially during the winter months, if I can't fly direct, I prefer airlines with southern hubs (Delta - Atlanta; USAir - Charlotte). I pick up another 500 miles each way, which, for me, is an extra 18,000 miles annually.

b) If I have a problem with an airline, I contact their customer service department with a detailed letter. If I don't hear back within 20 days, I send a clearly identified "second letter", and then try e-mail and faxing this to alternative departments. I have received extra miles and flight coupons in an effort to compensate me for my trouble.

c) Flying American? Check out the thread in American Airlines - "The Elite Challenge". The thread describes a quick way to go up an elite level or two (and pick up the extra bonus mileage that the level provides).

Intentionally cancelling a credit card with a negative mileage balance is akin to cancelling a credit card oweing them money and refusing to pay. I think that some credit cards may ask reimburesement for the negative mile balance. Not recommended, IMO.

Smetimes mileage credit cards offer miles for balance transfer. If this offer is made without cash advance charges, it is often worthwhile to get the miles (try to minimize any APR charges that you would incur in this case).

pgupta is right--if you are trying to maximize miles (not paying attention to time value of money) you might try getting one of the intro offers which offers miles on balance transfers, then write a check to the new credit card co, then do the balance transfer. You transfer a charge on top of a credit balance, thereby cancelling it out, and incurring no charges.

Also I have charged an item on a mileage-earning credit card and returned it and gotten credit on a non-mileage earning card. I don't do very often but if the customer service person isn't paying too much attention you're ok.

Princess Cruise Lines allows you to charge gambling chips to the room. When I heard about this 6 months ago I had the biggest smile on my face and my family thought it was because I was going on a cruise to the Caribbean! Imagine my disappointment when I read that there is a 3% service charge for all chips charged to the room... and it was a maximum of $5000 for the cruise.

I only fly once or twice a year and do not pay annual fees for credit cards. My tips:

1. Switch long distance phone carriers every month racking up 5000 mile bonuses. It is easy with three companies: AT&T (British Airways), Sprint (TWA) and all the airlines at MCI. I switch to MCI every other month.

2. When a free affinity card becomes available, I charge like crazy and take advantage of referral offers like United's refer one person to get the card, get 5000 miles deal. Christmas came in July in 1998.

1) When buying a car, you can pay a part of the total amount with a credit card - ask your BMW sales representative. I had CAD$23,000.00 charged to my AMEX last year.

2) With some telephone, cable, hydro companies, you can use your credit card to pay your bill every month - call and ask.

3) Some insurance companies will take credit cards for premium payments - call and ask.

4) If you own a business, get the American Express card for small businesses and subscribe to the Membership Rewards option ($50 annual fee; 1 mile per dollar spent). Charge all expenses to that card.

This is how you earn at least 7 miles per dollar. Sign up with MCI (5 miles/dollar) then have the bill automatically charged to your credit card A. Then transfer your balance A to credit card B (with a lower interest rate), etc.

As most of you know, I strive to earn as many free air miles online as possible. In my opinion, the best online resource is PlanetAll. After signing up, you earn 100 miles for each additional person that signs up. Ten signups equals 1000 miles on your choice of American, Continental, Delta or United.

Their service is absolutely free and quite useful too. Amazon.com recently purchased their entire operation.

Of course, if you plan to sign up, I won't complain if you let me earn referral credit.