This guide will help you create a good rocket, and introduces some basic skills.
NOTES: This is only for creating your rocket, not launching it. Please DO NOT use this guide if you are already good with KSP. This guide assumes you are using a creative world.

The Vehicle Assembly Building is the tall building in the center of your personal Kerbal Space Center. This is the building where you create your rockets.

PODS
A) As the name says, pods for manned rockets.
B) Cockpits for manned planes. (We won't use these yet.)
C) Drone cores for unmanned planes and rockets (We won't use these yet. These are for long-distance or high-risk rockets and planes, or satellites.)
FUEL TANKS
A) As the name suggests, fuel tanks, in three variants:
A1) Normal fuel tanks (all sizes.)
A2) Adapters (all sizes, standard and NCS)
A3) Radial (These are smaller, and go on the outside of your rocket or plane)
B) The fuel pipe and drain valve. (We won't use the drain valve yet; the fuel pipe is one-way from the starting section to the ending section.)
ENGINES
A) Inline liquid fuel engines
A1) Plane engines (We won't use these yet)
B) Radial liquid fuel engines
C) Inline solid fuel engines
D) Radial solid fuel engines
COMMAND AND CONTROL (We won't use anything from here yet)
A) RCS blocks and ports
B) Reaction wheels
C) The avionics hub
STRUCTURAL (We won't use anything from here except the strut connector and the launch stability enhancer)
A) Girder segments
B) Pylons
C) Adapters
D) The launch stability enhancer
E) Structural panels
F) Multi-point connectors
G) Structural tubes
H) I-beams and strut connector
COUPLING
A) Decouplers
B) Stack separators (We won't use this yet)
C) Docking ports (We won't use these yet)
D) Grabbing arms (We won't use these yet)
E) Radial decouplers
PAYLOAD
A) Cargo bays (We won't use these yet)
B) Fairings
AERODYNAMICS (We won't use any of these yet)
A) Plane wings
B) Fins & ailerons
C) Nose cones
D) Intakes
E) Airbrakes
F) Tailfins
GROUND
A) Airplane landing gear (We won't use these yet)
B) Rover wheels (We won't use these yet)
C) Landing legs
THERMAL
A) Heat shields (Please note that the 10m heat shield is better than the 1.875m shield, but has to be ejected and should have a 1.875m between it and your pod)
B) Radiators (We won't use these yet)
ELECTRICAL
A) Battery packs
B) Solar panels (You should use a mix of retractable and non-retractable)
COMMUNICATION
A) Antennas
SCIENCE
A) Labs
B) Scanners (We won't use these yet)
C) Smaller scientific modules like Mystery Goo Container
D) Science JR
UTILITY
A) Parachutes
B) Crew cabins (We won't use these yet)
C) Convert-O-Trons (We won't use these yet)
D) Flags (We won't use these yet)
E) Mobility enhancers
F) Drills
G) Hitchhiker storage
H) Launch Escape System (We won't use this yet)

For this guide, I am going to assume you are in Sandbox mode. In each section, you will choose your parts by a basic template, but you can choose the basics.
1. The pod
-This is the first part of the rocket to choose. Choose a pod; you don't need to move it yet. You may need to later.
2. The main parachute
-This is a vital component of your rocket. It's almost impossible to land correctly without one. Choose a parachute and place it on the green and black sphere on top of your pod; make sure it's the right size.* Choose an inline main parachute.
3. The drogue chutes
-This is another vital component. If you do not have radial drogue chutes, your main parachute will overheat. Click the gray circle with a yellow dot between 1 and 3 times. This is your radial controller. Next, take the radial drogue chute from "utility" and place it on the side of the pod.
4. The solar panels
These are to make sure that you don't run out of electricity. Choose some photovoltaic panels. Place them on your ship.
5. The heat shield
Choose a heat shield. Place it underneath your rocket.
6. The comms
Take an antenna and place it on the side of your ship.
Hopefully, your ship looks somewhat like this:

*this is true for all parts.

1. The decoupler
Choose the CORRECT decoupler and place it under your heat shield.
2. The fuel tank
Choose a fuel tank that you like. Place it under your decoupler.
3. The engines
Take a Thud (this is the only time I'm going to say you need a specific part) and place it on the side of your rocket with your Radial controller set to 4.
4. The heat shield
Choose another heat shield. Place it under your rocket.
5. The legs
Choose your landing legs. Place them in between your engines. Make sure to right-click them then click "start retracted".
This is my template:

Now it's time to go out. This means better boosters!
1. The decoupler
Take another decoupler, same as before. Place it under the heat shield.
2. The adapter
Choose an adapter. It should start with your current rocket size and end with the next size up.
3. The fuel tank
Choose a fuel tank. Remember, you just sized up.
4. The engine
Choose an inline engine. Place it under the fuel tank.
I lost my save, so this is my new template:

1. Decoupler
Yet again, choose a decoupler. Place it under your latest engine.
2. Fuel tank
Choose the largest fuel tank of your current diameter. Place it under your decoupler.
3. The engine
Choose the largest engine available for your current dimension and place it under your fuel tank.
4. The launch stabilizer
Set your radial controller to 2. Take this part and place it on the side of your rocket.
NOTE: I have DLCS, so I have some extra parts.

1. The decouplers
With your Radial controller still set to 2, place a radial decoupler on the side of a ship.
2. The fuel tanks
Place smaller fuel tanks on the decouplers.
3. The engines
Place an engine under the fuel tanks.
3. The fuel pipes
Take a fuel pipe and click first on the inside of the booster tanks, then the main fuel tank.
4. The noses
Place nosecones on top of the boosters.

Thank you for reading, and enjoy your rocket! Soon I'll be sending out a guide for actually launching your rocket!

Update: here it is!
Launching your rocket