1. You start the game. I usually start with lustful witch male, or ancient warrior. Used warrior because they could capture without collar (once per battle) in older versions, in newer it's lustful witch to increase lust and make capture easier, if intruder manages to pass Guardians somehow (implying he is strong and worth capturing ).
2. You mine some blocks to clear space and do mines. You need your gold mine and research mine. I prefer to search for patch with good gold income "blessing", but neutral will do as well. Don't forget to consider putting them in "circles" aka in 3x3 blocks with empty block in the middle, so you could place workshop in center later for extra income.
3. You place one of your starting characters on gold mine to get money, and click research mine manually, because no alternative. Level up at least your first one or two gold mines to maximum, then place workshop nearby as well.
4. You make 3-4 long thin corridor from entrance to room with your other character as guardian. Better to have long corridor filled with traps later.
4.5. Optionally here I move my "Throne room" in furthest part of dungeon from entrance. It's usually on the opposite side of the dungeon on any phase of game, just so I have more time if unexpectedly strong enemy will invade. Got raided successfully only once, in the beginning, while testing what would happen after.
5. You try catching raiding characters which are higher level then yours, while developing towards baths, healing stations and farms, for your characters to be self sustainable. But your FIRST PRIORITY is trade station. Because you need to trade better slaves. (upd. 19.x baths and farms are unlocked by default).
5.5 Start searching for slaves with good "working" talents, and place those in your priority buildings - gold mines and research labs.
6. You capture slaves using slave collars and any grenades you got. If you find weak slaves, you sell them and buy stronger ones. You buy more slave collars and grenades, as well as any recovery items. Alchemy was too cumbersome mechanic for me to craft them.
7. You can keep your initial slaves for entertainment, and weak slaves to work in mines, but keep few strong slaves, and sell-buy-capture when you see better one raiding you, or on market.
8. You buy gems to level up your fighters, but don't overdo. Before, gems were super efficient, on 18.x they are nerfed hard, so they do SOME, but not much.
9. By this point, you should be capable of defeating raiding parties, and you need Altar. You need to LURE IN (menu option called "Tempt Invaders..." under Altar menu, bottom right of screen, 3rd from the left) stronger raiders(so just choose highest level you can handle), defeat them, capture, and make them yours. Or sell them to buy better fighters.
10. By this point you have a lot of 0-10 lvl slaves which are workers, or children of your slaves you sell or keep because you like them, and few 50-100-200 lvl fighters. Don't bother upgrading low level slaves with gems any longer, it would cost you fortune and won't be effective anyway. It's faster and easier to wait for new day/roll of raiders you can lure in, untill one stronger than your slaves appears. So you LURE them in, bleed, poison, scare, seduce, and drop their sanity and HP to the point they stop resisting and agree to be captured by slave collar.
10.5 Technically here you can use graveyard and resurrect some strong invaders you failed to capture as zombies, but only if they were REALLY strong. They have positive sides, but I simply don't like zombies. Had few one, untill managed to capture raiders stronger than said zombies.
11. Get few more high level slaves and start sending them out for more gems. Not mandatory but got to have.
12. The further the day of progression is, the stronger raiders would come. If you did everything right, your guardians would be weaker than strongest attackers, but stronger than common one. So few of your guardians would be able to slay one strongest raider which you can LURE in manually. Then you capture them, and you have strongest unit. Untill there are stronger one you can LURE IN. Cycle and repeat.
That's the common cycle I'm going through since 15.x. There were some different things, like gems got nerfed, but besides this it's same. Some additions like re-rolling land plots blessings for better gold income and better food growth is optional, for when you have nothing else to do.