Once you have a solid destination in mind, it's time for lists.
Essential Information (see Research)
Maps
Weather and conditions
General plans based on historic data
Weather forecasts are only useful to a maximum of ten days so don't finalize your plans until then
Weather forecasts are only accurate to three days out, at which point you should track the conditions
Recreational goal
camping, hiking, bird watching, scenic drives, campfires, companions...
Resource list of links or printouts for on the go
maps, weather, campground agency website and phone, local government website (road information), local hospital...
Pack list
Gear list
I have different lists for backpacking trips versus long camping trips, different lists for summer and winter...
Meal Plan
Ideally a spreadsheet but at least a grocery list
Backpackers should plan by calorie intake but us lazy car campers only need to plan for cooler volume and budget
Personal Effects List
clothes
toiletries
gadgets
entertainments
Transportation
I just drive everywhere so I have
Vehicle to-do list (maintenance and repairs)
Vehicle fuel requirement calculations
Tool kit list
Packing diagram
If you use public or for-hire transport that needs its own plan
Hope that helps!