First, reach Level 7 in Barter to gain access to the Antiques Appraiser skill. This skill gives you a 5% (1/20) chance to sell junk for x50 its normal value. To guarantee the x50 money bonus, go to a vendor and give all your junk to the character with this skill. Sell the junk. If you do not get the x50 money bonus, simply buy everything back and try again. Repeat this process until you get the x50 bonus. You can get $30,000 payouts. Money is useful later in the game, when items start costing thousands of dollars. Even at Barter 10, you will need money. It is recommended to select one of your party members and make them a dedicated barter/crafter. This one person will barter, upgrade weapons, and generally help support your squad.
Quick leveling and stats building:
Set your leader to CHA 10 when starting Wasteland 3. At Charisma 10, you get a +30% XP bonus, but at Charisma 9, you only get a +10% XP bonus. At the character creation screen, you can immediately give your leader CHA 10 to get the XP bonus. All your stats will suffer early, but you will quickly outclass everyone else in your party. You will be earning skill points at a much higher rate -- so you can increase your other attributes quicker. The earlier you unlock the top tier of charisma, the more XP you will earn in the long-term. Since you cannot give everyone in your party CHA 10, it is recommended to give this to your leader for the bonus XP, while the rest of your team serves other purposes —- like upgrading weapons, bartering, lock-picking, hacking, and using a variety of weapons. Your leader is a fighter and a supporter -- so increasing charisma early will allow you to build a powerful leader that can heal and fight while giving your party a leadership boost. There is no easy way to farm XP, but at CHA 10, you will not need to farm.
Accomplish the indicated achievement to get the corresponding number of Gamerscore points:
Rookie (50 points): You beat the game on the easiest difficulty.
Wastelander (50 points): You beat the game on the normal difficulty.
Ranger (50 points): You beat the game on the hard difficulty.
Supreme Jerk (100 points): You beat the game on the hardest difficulty.
Tricked Out (10 points): You obtained all vehicle upgrades.
Mastery (10 points): You reached level 25.
Oops (10 points): You accidentally downed one of your own squad members.
Boomstick (10 points): You killed 4 enemies at once with a single shotgun attack.
Wasteland Reaper (10 points): You killed every living person in Downtown Colorado Springs.
Fire it Up (10 points): You killed an enemy with fire damage.
Gooification (10 points): You liquefied an enemy with energy damage.
Cold Reception (10 points): You shattered a frozen enemy.
Badda Bing (10 points): You blew up 6 enemies with a single explosive attack.
Mod Master (10 points): You installed 4 weapon mods on a single weapon.
Body Builder (10 points): You got modded, and can now install cyborg parts.
Toaster Expert (10 points): You truly earned your toaster repair diploma.
Illuminati (10 points): You uncovered the darkest of conspiracies.
A New Home (10 points): You unlocked all the major room upgrades to Ranger HQ.
Expedition (10 points): You discovered every location on the World Map.
Back in the Sack (10 points): You collected all STDs in the Wasteland.
What's In This Thing? (10 points): You ate a Clown Burger.
Double the Fun (10 points): You brought Billy and Jean all the way to the end of the game.
Menagerie (10 points): You tamed at least one of every type of animal companion.
My Pretties (10 points): You amassed a collection that would terrify a toy shop owner.
Roadkill (10 points): You give hit-and-run a new meaning.
Chop Shop Champ (10 points): You upgraded your vehicle to the highest level.
Scorpitron Slayer (10 points): You took down a Scorpitron, in proud Ranger tradition.
Answering Machine (10 points): You found all the cassette tapes left around Colorado.
Restraint (10 points): You resisted temptation and never opened the Mysterious Case.
Fixer Upper (10 points): You found the Kodiak.
Additionally, there are 32 secret achievements:
On Your Own (20 points): Your commanding officer was killed in action. It's your mission now.
No-Show (20 points): You never made it to Colorado Springs.
The New Law (20 points): You established a new Ranger HQ in Colorado.
Won One for the Gipper (20 points): You overwrote Valor Buchanan's mind with God-President Reagan.
Stolen Valor (20 points): You arrested Valor Buchanan.
Valor's End (20 points): You killed Valor Buchanan.
Victory Over Victory (25 points): You killed Victory Buchanan.
Caged Psycho (25 points): You arrested Victory Buchanan.
Give Me Liberty, Or... (35 points): You killed Liberty Buchanan.
Un-Lib-erated (35 points): You arrested Liberty Buchanan.
New Colorado Order (20 points): You deposed the Patriarch and liberated Colorado from his rule.
Dead Red (20 points): You defeated Angela Deth and stopped a coup.
November Reigns (20 points): Team November and the Rangers have taken over Colorado.
Morningstar (10 points): You answered Morningstar's call and gave him a new home.
Bunker Buster (10 points): You set off Morningstar's self-destruct mechanism.
Hoon Hero (10 points): You dealt with Erastus Dorsey before he could harm the Hoon family.
The Needs of the Many (10 points): You saved the shipment of power armor from the Scar Collectors.
No Time For Distractions (10 points): You allowed the Hoons to be murdered and the power armor to be stolen.
The Marshal (10 points): Darius Kwon has offered to join your party.
The Gunslinger (10 points): Lucia Wesson has offered to join your party.
The Warlord (10 points): Ironclad Cordite has offered to join your party.
The Psychopath (10 points): Victory Buchanan has offered to join your party.
The Scientist (10 points): Pizepi Joren has offered to join your party.
The Hobo (10 points): Scotchmo has offered to join your party.
The Hard-Head (10 points): Fish-Lips has offered to join your party.
Book Learnin' (10 points): You found every lore book in the game.
Heads Up! (10 points): You threw a snowball at an NPC or party member.
I, Human (10 points): You convinced the Machine Commune that humans can be trusted.
Everyone Lives (10 points): You saved all the hostages in Aspen.
Pre-Apocalyptic Tourist (10 points): You sat through Quarex' entire museum tour.
Quid Agit?! (10 points): You found the Provost.
Bawk! (10 points): You assembled Poultron.