Here is a small list of proven ways to increase your fortune:
1). Keyruns. This is a guaranteed way to increase your wealth. You will need the proper build and equipment, but it shouldn't cost you much. Countess, Summoner, and Nihl are easy, you just have to figure out the patterns for the maps. This method takes time and patience, but you will be rewarded. If you want the most bang for your keys, you may want to collect organs and sell them as sets.
Ideally, you want to reach the highest breakpoints for teleport, but make due with what you can afford.
2). Midlevel Super-Unique Boss Runs. Mephisto, Diablo, Andariel, Shenk, Eldritch, and Travincal can drop fairly high level items. Maras, Hoz, Sojs, Arachnids, etc can be had from these. I usually sell the perfect versions of these items and use an 'inferior' version for profit. If you find items worth pgems, make a game called 'X-item 4 x-pgems' while you are doing runs ('Shaftstop4 8pgms' for example). This way you're making currency while MF-ing and finding a use for low lvl items.
3). Highlevel Super-Unique Boss Runs, or Baal MF runs. Baal can drop some very valuable items (Crown of Ages, Griffons). It will take some time, but valuables will drop eventually from Baal. The two aforementioned items alone can net you a respectful fortune if you get good rolls on them.
SoJ = 1.5 to 2hrs on ESCL as a reference. 1os CoA = 2-4 hrs. 2os 15dr CoA = 10+ hrs. 2os 15dr, 30res CoA = 20-25 hrs. My point is, that one item can turn the tide from eating at Harrograth's Cart-Horse Diner, or Lut Goleins' 5star BBQ steak house. The same example applies to Griffons, as it goes for comparable rates (although even a crappy Griffons will go for alot).
Highly valuable Runeword items are also a benefit of doing Baal runs. Baal's minions can drop everything in the game, so there's a chance (an astronomically small chance), that an etheral Vortex shield with resists (for example) could drop. Eth ZA, CB, polearms, etc are fair game. Superior version of sought after items goes for that much more.
If you find an Eth Vortex Shield with 40+ resists, glitch that baby. If you roll a 500 def one with 4os, you just made a fortune right there. 20+hrs easy.
4). Desperate People. Find the right buyer, especially at night when there aren't many trades going on. That is when people are usually desperate. If someone is paying 2 or 3 times what something is worth, make the trade happen.
Moral of the story: Luck, luck, luck, hardwork, and patience (with a hint of knowledge) will land you 2 barbarian, hot mommas to warm you up during those cold winter Harrogath months. Maybe even a 4 x 40/15ias'd, well hung Stallion to impress Anya (or Mala if you're into that kind of stuff ><). :grin: