This topic is to provide some information about how to optimize your experience in Clear Sky. This is not about mods, it is just about how to use existing content to the max.

First things first:
Grab what you can. Always drop off loot at the green boxes. Pick a few convenient ones. Mine are:
-Swamps: Machine Yard (right next to the guide)
-Garbage: Fleamarket (right next to the trader)
-Agroprom: Loner Base (in third floor, above trader)
-Cordon: Neutral Base (right next to the entrance to the inner region)
-Red Forest: Tower at Bridge, second floor and Duty post, close to Forrester
-Military Warehouses: At the Freedom post on the hill to the left when you come from Garbage

When you start the game and are still associated with Clear Sky, grab the Sunrise Suit while you still can. It is the most important suit until you get the SEVA suit and it's much cheaper compared to later on in the game.

Important: don't kill every bandit on sight before you get the SEVA suit upgraded. You'll bite yourself if you do. Be extra careful in Agroprom about this, because you're inclined to help the Loners a lot against bandits.

Respond to every call for help from Clear Sky in the beginning for you get rewards. Use it. Don't explore just yet, only when you're free to go to other regions.

Don't take any "Bring me.." missions until you can complete them (read: until you get the SEVA suit). You can't do any other missions of the same kind when there is one of these open.

If at some point you get the answer "You can't help me" although you have none of these return missions open, just go back to where you didn't do all of them and do one or two. Most likely Cordon.

Don't sell everything at Clear Sky. Instead, get associated with Loners and sell the following weapons always there:
AK 74, AKMu, Viper, Hunting Rifle, Chaser. You'll get loads of them and when you're associated with the Loners, you can travel from Agroprom (my mainstay) to Neutral Base and back for half the price - and the trader pricing for these items is equal or even better than at Clear Sky Base.
Everything else is to be sold at Clear Sky.

When you enter Red Forest, Fast Travel won't be available to Clear Sky Base directly anymore. Instead go to Machine Yard and then hike to the Fishing Hamlet.
So be sure to drop off all valuable guns at Clear Sky before you enter Red Forest, as from then on you'll have to hike.

That's it so far!

Well, one last note:

Get the scanner and the Gravi artifact in the swamps first thing when you're free to go! It's in a small cave to the top left under a railway bridge. The entrance through the fence is quite a bit farther to the right.

You want those weapons:
Chaser - this is your mainstay against mutants. Fully upgrade it, you won't let go of this.

TRs - fully upgrade this for accuracy. Until you get the GP 37 this is your weapon of choice. You can refit it for russian ammunition so you save NATO munitions for the GP 37.

later on:
GP 37 (get it first thing in the Military Warehouses). Fully upgrade for accuracy.
Warning: by that point you'll most likely have a Fireball artifact or whatever the name is that you have to return for the GP 37. Drop it before you hand in the one from the house, or you'll give it away sometimes for no reward. You can pick it up later with the scanner again.

RP-74 or whatever the name of the machine gun is. How to get it early on:
Join Duty, clear Agroprom from Bandits (mind the SEVA suit! You can also do this with Loners before, then just wait a minute until you get the Agroprom is cleared message). Then you can buy it from their trader.
Then you can join the Loners again if you like. Fully upgrade this for fire rate. This is the most fun weapon in the game, albeit a bit costly on ammunition.