The commissions are the "dailies" of the game. You unlock this when you reach Adventurer Rank 12. These tasks are different each day, and every day there are only 4 tasks. Look around the map for the daily icons and clear them out, they are mostly pretty easy and can be cleared out fast. Once you are done. Talk to the Adventurers' Guild to receive your rewards.
Closely related to the commissions, the battle pass also has daily tasks that you're going to want to complete every day. You unlock the Battle Pass at Adventurer Rank 20. Unlike the commissions though, the daily tasks here is always the same, but it requires you to do the 4 commissions so might as well do it together. Explore around the map for the commissions then mine some rocks if you happen to find any.
One of the things that you need to do for the Battle Pass daily, which is to use 150 total resin. Since you can only hold up to 120, you will pretty much need to use some, and then wait for it to recover by 30 (8 mins for 1 = 240 minutes, or 4 hours). You might need to plan ahead to clear the 150 resins required, otherwise you will have to use some recovers using primogems or fragile resin.
What should you use your resin for? Go to the adventurer's handbook, or press F1 if you are on pc, then check the domains or bosses tab and see the ones that require some resin. Early on, you can go for the leylines to get some gold or character exp. Once you want to ascend your characters at lvl 20, then go to domains and go to the ones that give your required materials.
You can unlock this feature once you reach Adventurer Rank 14 and talk to the Adventurers' guild in Mondstadt. Expedition lets you use some of your unused characters to go out and find some materials for you. There are ores, food materials, and/or some gold. There are some characters with a passive that can reduce expedition time by a certain amount like Bennett
More on the optional side, but the food items that you can buy in towns are refreshed daily (or more than a day sometimes). Sara in Mondstadt sells food items that you usually need to "process", and this takes real time to make, so buying some can be a lot faster, but of course it can get expensive if you buy out the entire thing daily. Right across Sara is another food item shop to buy some food materials, except they are not "processed" items.
There is also another "process"ed food items vendor in Liyue, and the stock is not shared with the one in Mondstadt. If you have plenty of mora, you can buy all of them from both shops to save you some time processing.
The ores have different respawn times, which is based on the time that you take them, not based on server reset. So make sure you do these when you get the chance!
You can farm certain artifacts for free without using resin by defeating Elite enemies out in the world. These enemies spawns every day, so it's best to do them every day to take advantage of it. The page linked below shows only a couple of easy to do areas with plenty of Elites.