When you get a new RV for the first time or just getting back into RV camping, its hard to know everything you need.  Below is a base list of things you may need and could be used as a baseline when you are packing.  Feel free to add items in the comments to keep building the list.

RV Essentials:

• Surge protector
• Electrical adapters (50amp to 30amp AND/OR 110v to 50amp)
• Toilet chemicals
• Sewer kit
• RV-friendly toilet paper (if you use your home toilet paper it will cause some serious black tank issues that just isn't worth it)
• Water pressure regulator
• Drinking water hose (you may want two or a longer one since some parks put there water supply in very weird locations which can be far)
• Leveling blocks (used when the ground is really really not level you can drive a side of your RV on these to help even it up some)
• Tire pressure gauge (be careful of anything electronic since you don't always use it, when you need it you will want it to just work instead of hunting for batteries)
• Extension cords (can be expensive for a 50amp cord but totally worth it when its hot out and you want to use your A/C units)
• Wheel chocks (attached a link to the most common and most highly rated by a ton on Amazon for wheel chocks)
• Shovel
• Electrical and duct tape
• Extra cotter pins
• Extra motor oil and transmission fluid
• Flashlight
• Battery jumper cables
• Emergency road kit
• Fire extinguisher
• Large zip close bag for documents, including license, registration, reservations, etc.

Kitchen and cooking supplies:

• Water bottles
• Cutting board
• Utensils/cutting knives
• Can opener
• Tongs and skewers
• Dish soap
• Camping griddle and pie iron
• Bowls, plates and cups
• Paper towels
• Garbage bags
• Plastic wrap
• Zip close bags 
• Potholders
• Dish towels
• Napkins
• Measuring Cups
• Measuring Spoons
• Skillets (we prefer cast iron skillets)
• Disinfecting wipes
• Matches and lighter
• Food storage container
• Cooler
• Coffee Maker
• Coffee Filters
• Coffee Grinder 

Food staples:

• Batter mixes
• Vegetables and fruits
• Butter or margarine
• Cereal
• Condiments, including mayo, ketchup, mustard, relish, etc.
• Grill meats, like hot dogs, burgers, brats, etc.
• Drink mix packets
• Eggs
• S’more ingredients
• Freeze dried meals
• Salt, pepper, herbs and spices
• Bread
• Baking items, including flour, cornmeal, sugar, etc.
• Canned foods
• Peanut butter and jelly 
• Snacks, including crackers, chips, pretzels, etc.
• Cooking spray or oil
• Soups
• Coffee

Clothing and bedroom items:

• Hat
• Rain gear
• Shoes, including sneakers, hiking boots, sandals, etc.
• Bathing suit
• Sweatshirts and jackets
• Socks
• Underwear
• Pants and shorts
• Short and long sleeve t-shirts
• Clothes hangers
• Alarm clock
• Sewing kit
• Towels
• Sheets and blankets
• Pillows

Personal items and toiletries:

• Phone chargers
• Cash and credit cards
• Reservation confirmations
• First-aid kit
• Sunscreen
• Bug spray
• Batteries
• Watch
• Medications and prescriptions
• Glasses or contact lenses
• Sunglasses
• Travel map and campground directory
• Soap
• Shampoo and conditioner
• Brush and comb
• Toothbrush
• Toothpaste
• Floss
• Deodorant
• Hair ties
• Lotion
• Makeup
• Razor
• Shaving gel
• Nail clippers

Camping and outdoor fun gear:

• Camera
• Wood
• Camping chairs
• Hammock
• Frisbee
• Fishing gear, including rods, tackle, license, etc.
• Sports equipment, including football, basketball, baseball, mitt, etc.
• Bicycles, scooters
• Yard games, including corn hole, horseshoes, hula-hoops, etc.
• Binoculars
• Books and magazines (rain day)
• Playing cards (rain day)
• Board games (rain day)
• Puzzles (rain day)
• Movies (rain day)
• Radio
• Headphones
• Notepad or journal
• Laptop
• Saw or hatchet
• Flotation devices
• Guitar 

Again for you experienced RV Campers, what is missing from the list that should get added to help those that like to follow lists.