So, you want to get rich quick? Well too bad, getting rich takes some time - but here's how you can do it.
So, you're ready to make some money. Good choice! Before we get into how to do it, here's what you should start with: Make sure you select 14k. You can start with 10 if you like, but it'll be more difficult if you do that. When you get into the game, pause immediately and buy the mine - then move on to the how-to part of this guide.
After you upgraded the mine cart to level 3, get the 'High Quality Picks' upgrade for the mine. This gives you +0.4 mining speed. Upgrade your workspace to the highest level you can. If you want, buy the 'More Tools' upgrade so you can get the maximum amount of workers. I reccommend hiring only males (sorry females!) because if a female gets pregnant they can't work. Put at least 2 people on gems (or more if you'd like) and the rest on gold, iron, or silver - whichever one you can make the most money off of. For your house get the pet dog and set it to stay at home (by right-clicking on it and selecting 'Go Home'). This prevents from people: A. Setting your house on fire - and B. Making it so people can't break into it. The dog will alert guards if it sees anyone messing with your house. After each day's work, put all your ores into the cart (unless you want to stockpile them for later) so that the mine's inventory space doesn't fill up. Make sure you check your town's market, the other towns', and the traveling merchant's (if there is one) and sell it to the one who is paying the most. (Buying price is the upper yellow bag and selling price is the lower orange bag). Then just let everything play out and soon you'll be rolling in the yellow stuff. Hopefully.
Tips & Tricks
Here are some tips & tricks for making sure your attention is on the money making - although you probably expected that from the name of this section. First, make sure you stand in the place where you see the most foot traffic and entertain (or beg, pickpocket, etc. Whatever makes you happy) so you get some extra money. Next, make sure you never buy food - just forage in the trees or bushes for vegtables or fruit and eat those. Also, I reccommend getting a spouse and child as soon as you can so you don't have to worry about doing that later.