You should get this in the first area, Grashugel Forest.
These were the missions I had to complete before an upgrade was earned:
Getting Around
Tranquil Transmission
Clear the Road
Case of the Birdy Bandit - Ranger Ryan needs his keys from the nearby bird nest.
Picnic Basket Plunderers - Clear 3 picnic sites of monsters.
Troublesome Tunes - Enter and shut down the first concert of the evil DJ, Lord Decibel.
Campground Cookout - Collect 10 pieces of firewood and get Grandpa's fire going.
After completing Campground Cookout, the Rust Bucket camper will be fixed and Grandpa lets you use it for stuff.
You'll be given a choice to upgrade 1 of 3 attributes:
Toughness - Lower damage taken
Power - Increase combat damage
Luck - Earn more loot and increase chance for a Lucky Shot
Pick one and this achievement will pop.