Starting out by mining iron is very safe but can be boring, first time I did that I also played it too safe and didn't really do anything. There are abandoned towns you can find with a lot of stuff to sell that I think is more enjoyable. Iron however is very great for strength training. To get the max bonus for strength training you need to be very encumbered and carrying someone. Shift clicking on a lot of things will set that character to do a job so you can automate strength and athletics training.

Dark ui mod is extremely good and worth using, https://www.nexusmods.com/kenshi/mods/253. There are also a few performance mods that are worth it if the loading times bothers you. Making simple mods yourself isn't that hard, like giving your faction its own color or creating a custom start. The game has a bug where your turret guards may end up falling through the floor when reloading, one of the big utility/performance mods fixes this. You can also only build turrets on the big walls, not the tiny connectors.

Building bases directly on roads will break ai very frequently, I don't remember the keybinds off the top of my head but you can view roads in game with some dev toolset.

Healing enemies you down is worth it for xp and, if one is alive to see you do it, it will increase your rep with that faction slightly.

You get more xp from combat by being disadvantaged, either by fighting someone stronger than you or purposefully weakening yourself.

Animals level a bit differently, they have ages they go through and they gain more xp when they're younger I think. They also cannot lose limbs.

You can ally with the starving bandits, generally at the start of a game they will initially be friendly and approach you asking for food. I think any of the none aggressive options improve relations and giving them food can be worth it. Dealing with constant starving bandit raids generally just becomes annoying later on.