In Xenoblade Chronicles X you have three field skills you need to upgrade in order to find treasure and relics. They all start at level one but in order to upgrade them you will have to find a certain character in game. Check out this guide to find out How To Upgrade Your Field Skills In Xenoblade Chronicles X!
You cannot upgrade your field skills until after you become a Blade Member fully and gain access to the Blade Barracks. The three field skills are Mechanical, Biology and Archaeology. You will need to level each one up separately but you should focus on getting Mechanical to level 3 first so you can plant all the Probes in Primordia.
You can find the person you need to talk to to upgrade the skill across from the Blade Barracks. Her name is Elronora and you will need to level up your Blade rank in order to gain access to more Field Skill upgrades.
To upgrade the Blade Skill you will have to do numerous things. You get points from killing enemies, picking up loot crystals, finding artifacts or damaged Skells (any type of field skill gives you points) and doing quests. Pretty much anything you would do for your division will give you points to your Blade rank. It is easy to level up early but it quickly becomes a big bar.
The more you play the easier it will be to rank up the Blade skill and each time you level up you can upgrade a Field Skill!