Pretty good advice all around. BUT. here's how I do things.
1- Re-read the Archive of Wisdom carefully. Its the best jumping off info.
2- Re-read the ride instructions for your choice of ride. I have never had to ask what any of the instruction mean. They have always seemed crystal clear to me. In fact I have used them as an example of how to get it done right in the first place.
3- Experience is the only teacher I trust. More experience, better wisdom.
4- Run the fuel down to the idjit light and top it up asap. Do it until you are comfortable with the number. Now you know how reliable the mileage is for the idjit light.
5- Run the bike down to zero mark and top-up asap. After a bunch of times, you will get familiar enough that it won't scare you to do that. Pack 2 qts of fuel if you need to lessen the anxiety.
6- I usually run a new-to-me bike empty at least once. I have never damaged a fuel pump and see no reason for me to worry about it. If the manufacturer put in a crappy fuel pump, the word would soon be out. Put in a carefully measured amount of fuel and ride to gas. Note the quantity to top -up. You now know exactly how much fuel is needed to fire the bike. You also know how much the tank actually holds. Plastic tanks swell with age and heat and may hold as much as 1/2gal more than the factory specs.
7- You could drain the fuel system and fill to measure. If done in the cool and comfort of the garage, it may not give the same spec as if it was done in the heat? I have never felt the need to to get this level of accuracy.
8- I figure 20 miles of reserve fuel for east of the Mississippi R and 40 miles west in the Good Ol' U.S.of A. Out of country is not my forte. I did go twice to the Far North where fuel was rare. First trip I had plumbed aux fuel and used some. Second trip I packed 4g Rotopax and didn't need any of it.
9- I have developed riding fuel 'modes'. Basically, I know at what speed and conditions I can ride to give me my best mpg. Start at 40mph and work up/down from there. An aerodynamic bike might have a sweet spot at 60mph. Fold in the highway pegs and tuck in and a Wing might give much better mpg than ever before. Adjustable windshields might give huge increases when set to the right height. Pack gear on the bike with some thought to the aero's. Putting a duffel of light stuff on the pillion to fill the void between the pilot and the tail/top case might increase mpg by 3-4.
10- On a chain drive bike, use the biggest CS sprocket available all the time. On an LD ride, drag starts are never needed. Ride like you need the mileage and not the time.
11- Comfort stops should be planned and executed with the same loving care as fuel stops. I use the "100 mile get-Off" technique sometimes known as the "Half Tank Get-Off". Like the AOW says, "Slow down to go further". I use a stopwatch velcro'd to the bike just for this comfort stop. At about the desired mileage of the stop, I find a convenient safe place to park. I start the watch and get off the bike. I have a nearly choreographed stretching exercise routine (informed by a Pilates instructor) that takes me around the bike for a visual inspection. There is time for hydration and noshing while replenishing supplies, think dancing and working. If I gotta take off the helmet for a scalp scratch and some air, so be it. The idea is to get really refreshed in 2 minutes by the clock and get back on so as not to waste time. The 2 minute drill repeats at fuel stops, meal stops, and any place/time that it might get worked in. Sure the bike seat/cockpit is as comfortable as you can make it. The "100 Mile Get-Off" makes it feel delicious every time you get back on. Especially if you are as unholy old as me.
12- Have a super econo-mode and know how to use it. Out west, it is amazing how I can get to remote fuel on fumes to find out that the station power is out and fuel cannot be pumped (even manually, grrr, sigh. Buy some from people waiting for fuel if you can. A half gallon might just get you to the next town where the power is still working. Phone ahead to make sure.). Ride up the hills and switch off to coast down. Carry siphon gear and a tow strap. Walk to the nearest farm house/habitat and offer to buy garden tool fuel at a very very good price. 2-stroke fuel will burn in a modern bike most times. Diesel will run in some 4-strikes poorly enough to get to a station where it can be diluted with premium.
13- Stopping while "on the clock" is much different than rides with plenty of time to get a cert. Develop a comfortable fuel stop routine and time it so that you know what you are reliably working with. By example, I can get everything I need to do at a fuel stop done in 12 minutes, 10 if I need to hurry. If I am 'on the clock', 5 minutes is what I need for a top-up splash&dash.
In sum, all my riding is planned and used as practice and experimentation for when I might have to do it later when it counts. Its been fun leading club group rides and telling noobs that fuel stops will be <12 minutes or they will be left. Having a 'crisis potty stop' group signal is fun too. Ever have a riding budd BEG for a potty stop?
14- Unless the aero's are really good and known to the rider, speeds above 80 will be self defeating over the long term. It is tiring to ride that fast for long periods. If cruise control or throttle loc is not available, speeds will vary more as the rider tires. Bad for fuel mpg and bad for safety all around. Rally Nominal is another topic. Even one roadside performance discussion will wreck the timing of the whole day. Some day the IBR will be set up to give real advantage to mpg and the wingabagoes and autobahn'rs will suffer mightily. Why significant boni pts are not awarded to high mpg riders at the scoring and lauded at the banquet escapes me? Rider with the worst mpg should get teased too. Riders who consistently fill with less than a 1/2gal remaining might be noted? Some interesting fun could be had with mpg?