Use the Quick Inventory Menu
A handy feature in Fallout 4 is its quick-select inventory menu, which you can utilize to switch weapons or use items during gameplay. To use it, go into your Pip-Boy and highlight the item you want to assign and press R1/RB.
This will bring up an "Assign Favorites" menu (pictured above) that you can promptly slot the desired item into. Using this can mean a healing stimpak is just two button presses away, as opposed to having to drill down through several menus.
Holster Your Weapon to Run Faster
It may not seem super obvious at first but when you holster your weapon, your character actually runs faster. This can be useful when you're in a pinch and need to retreat. To holster your weapon, simply press and hold the Square/X button.
Sleep to Regenerate Health
If you're ever low on health, you can sleep to recover HP (health points). To do so, go up to any mattress or bed and press the X/A button. You will then be asked to set how many hours you want to sleep. Depending on how long you're out for, a certain amount of your HP will refill.
It's worth noting that you can do this to any unowned mattresses or beds, regardless of whether your location. So even if you're in the middle of infiltrating a raider's camp, if there's no one around, you can sleep and heal to save on stimpaks. But if there are any enemies nearby, they will halt the recovery process and start attacking you.
Power Armor Can Be Stolen
If you're ever wandering the Wasteland and decide to get out of Power Armor, make sure you don't leave it alone for too long. If you're not careful, it can actually be stolen. Be sure to remove armor's Fusion Core from the back if you ever decide to leave it behind for any period of time. That way, the suit will be useless to any raiders who might attempt to take it from you.
Return Overdue Library Books
As you explore the Wasteland, you can find overdue library books. If you insert them into the book return terminals of the respective libraries they belong to, you'll receive a token. You can then use these tokens at the terminal to redeem useful items.
Get More Quest XP
If you're ever about to turn in a quest to an NPC, make sure to equip any items in your inventory that boost your intelligence. This will increase the amount of XP you receive upon completing the quest.
Like V.A.T.S.? Here's How to Improve it
V.A.T.S. is a vital tool for any Fallout player that can be improved exponentially by assigning points into the right attributes and perks. Look to assigning points into perception, agility, intelligence, and luck.
Perception can get you Awareness at PER 3, granting you the ability to see enemy weaknesses in V.A.T.S. You can also gain increased accuracy in V.A.T.S. with Concentrated Fire at PER 10.
In Agility, your Action Points recharge rate can increase with Action Boy/Girl at AGI 5. Gun-Fu at AGI 10 allows you to inflict increased damage to every consecutive enemy after the first.
Intelligence can give you V.A.N.S. at INT 1, which marks the closest quest target in V.A.T.S.
Luck has Critical Banker at LCK 7, a perk that lets you save a Critical Hit to use at anytime in V.A.T.S.
Keep Your Companion's First Weapon
It's important to know that your companion's starting weapon has infinite ammo, while the new weapons you give them don't. So when you first start to customize your companion's equipment, make sure not to discard or sell it. This can be a handy way to save ammo if you're ever running short during combat.
Certain Clothes Provide Better Vendor Rates
Don't hesitate to dress yourself before going out to shop. If you wear equipment that increases your charisma, you can actually get better buying and selling rates from vendors.
Sort Items In Your Pip-Boy
Are you having trouble sorting through your inventory? Using your Pip-Boy, it's actually possible to organize your weapons and items by damage value and weight by clicking the left analog stick. This might seem like a simple concept that's clearly marked in the HUD, but you'd be surprised at how easy it is to ignore the bottom half the screen completely.