The single best way to maximize the gold you make from dungeons is to get a dedicated group with experience in the dungeons you want to run. Gather some friends or find a guild who specializes in dungeon running. Find four other people who have dungeon experience and are willing to run, say, 10 dungeons with you every day for a week or two.
If some of the people in the group don't have experience in the dungeons you'll be running, go through the guides: http://gw2dungeons.net. If everyone is comfortable skipping, learn where you can skip fights.
If you know the people you're running with, you won't have to deal with the group finder, which means 0 downtime between runs, and you don't have to worry about getting stuck with unskilled or unpleasant players. And if you run with the same people for a couple days, even a group with average skills can start working like a well-oiled machine.
You can further improve your runs by tuning your group's gear and build. The most important thing is to make sure everyone is using a build specifically for dungeons. As for gear, full berserker gear and stats will help you clear dungeons faster, provided that everyone can stay alive as a glass cannon. If not, you might save time by switching a few pieces for tankier gear. There's no shame in tuning your gear to your ability level - this is one of the great features of guild wars 2.
Finally, you can tune your group's class composition. I know the hardcore farmers love their 'zerker warriors, but don't feel obligated to do whatever's popular in the meta. Instead, figure out what classes everyone in the group has leveled up, geared up, and are comfortable playing. Then check the gw2dungeons.net guides. They have loads of class-specific advice for different areas and encounters, and you may want to take advantage by, say, bringing your mesmer to a particular dungeon for positioning, or your thief to make skipping easier.
On a side note, if you're looking for a quick, one-time infusion of gold, you might want to take a look at your wallet and bank. Depending on your habits, you can make quite a bit by selling stored materials, old minis, etc. Or by spending karma on Lost Orrian Jewelry Boxes, spending skill points on material upgrades, or spending WvW badges on seige.