If you're not that far into the game, this video by cutedog is very good(although its 40 mins). But I'll try to summarize the most important stuff:
1) It is all about efficiency. The best way to make the most money, magic finding or not, is to just do as many maps as you can, as fast as you can. Granted, actual speed depends on your build/gear.
2) To address efficiency, look at what you are doing during and in between maps. How many seconds/minutes do you spend selling shit to a vendor, stashing your currency/map/items, rolling maps, etc.?
Easiest methods of addressing efficiency:
1) Roll all your maps at once that you plan to run. For example, you are gonna run 7 T10 maps, 5 T9 maps, 11 T8 maps. Roll them all, now. Spend the same time rerolling maps that have mods your build can't do.
2) Have a dump tab(s). This is essentially where you dump every piece of loot you pick up at the end of each map. No selling to vendor, no sorting and stashing. Just open this up, and dump everything in here. You will come back and sell/sort once all your maps are done.
3) Loot filter has to be set to where you are financially in the game(I will be using Neversinks as an example). If this is your first character, you will be doing a lot of the chaos recipe. That's fine. Set it to semi-strict(no one should ever set this to lower than semi-strict, ever). Pick up pieces of gear that are upgrades for you, or that you need to for your chaos recipe. A 2h marauder does not need quivers, and an arc trapper does not need swords.
Once your gear is decent, and you have a ok amount of chaos, set it to strict. This is what I use most of the time. At this point, I only do the unID'd chaos recipe off of boss drops only(I don't pick up much during the run, but I always say that if I portal back, I should bring as much as I can with me. This is personal preference). Your character should be able to fly through and 1-2 shot packs at this point.
On to more high level/meta money making methods:
1) I make a ton of exalts crafting high level abyss jewels, specifically murderous eye(red melee) jewel. It is easy to get them if you have zana 7 and t16s as you can use her mod to force an abyss to spawn in your map. It helps to know what the meta builds that use these jewels are and craft for them.
2) Currency flipping. I've never done this(very well anyways), but the principle is simple. Buy low, sell high. What's the easiest way to do that? Use
PoE Currency. You will click on "Manage your Shops." At this point you will need to set up your account with poe trade by sending a message to a specific account on the official forums(the website will guide you through it). After that, you can set prices on currency that you wish to buy and things you wish to sell. You will then set your price to something favourable, such as "I will buy exalts at 115 chaos each." At the same time, you can also put up "I will sell exalts at 125c each." Now who in their right minds will sell you exalts at that price knowing that they can sell for 125? Well, lots of factors. Time of day. Good uber lab drives fragment prices up. Sellers are AFK, so people will go down the list if they are desperate. If you put a big order, such as "I will buy 10 exalts at 110 each", many people will do that just because you have 10 exalts of sale; they don't have to dick around for 10 separate trades @ 120. Many other reasons I probably don't know, so perhaps others can chime in on this.
3) Carries. Got an easy Uber Lab day? Carry noobs for their loot. Can kill guardians/shaper? 5-10c per head. Good at Encounters VI? 10-35c I've seen this league.
4) Magic Find Windripper doing 72 burial chambers an hour. Yeah have fun with that lol.
5) Run uber lab, get good enchants on popular hats. Starkonja's, Indigon, high Ilvl shaped/elder bases, Mind of the Council, etc. You will have to look up what builds are meta, but arc / double strike / tornado shot / molten strike are some good ones.
6) Uber Elder. My personal favourite. I just really enjoy challenging fights, and sometimes you just get a jewel thats worth 30 ex. Best of both worlds! But uh, good be pretty good at fight mechanics. And be ok with loser several shaper sets learning the fight.
Hope this helps.