Love that game!

How to get to the Mün: an easy guide:

1. Start off with only 1 Kerbal. Work your way up from there.

2. Keep the engines sensible. There's no point using massive engines if you have to constantly throttle them down; plus you'll waste heaps of fuel.

3. Don't take too much fuel. A full fuel tank roughly twice the size of the command module connected to the smallest engine (the one withthe highest isp) that fits the size of the tank.

4. Remember ladders (mobility enhancers).

5. Use staging, but any more than 3 stages is too many. Ideally, you should use asparagus staging (tutorial here) but for the Mün that isn't really nessecary.

6. Your first stage should have horizontal as well as vertical decouplers. Play around with various symmetry modes until you get there.

7. Remember parachutes (1 XL parachute is enough), solar panels (2), batteries, and landing gear.

8. RCS tanks and thrusters are important to get right. Toggle on the "centre of gravity" view in the VAB and arrange the thrusters and tanks symmetrically around this point.

FLYING YOUR ROCKET

Assuming your rocket has sufficient structural integritty (if not apply struts liberally), this guide SHOULD work.

1. Blast off using MAXIMUM POWAH
2. If your velocity exceeds 200 m/s while under 10,000m; reduce power
3. Travel directly up, then turn right (pressing the d key) until you're 45° to vertical, and increase power to maximum.
4. Switch to Map View and pull up the navball.
5. Continue thrusting and jettisoning stages until tou get into an orbit around Kerbin with an apoapsis (marked as Ap) is over 80,000 m.
6. Burn prograde at apoapsis until your orbit is just about circular. (Maneuver nodes help a lot).
7. QUICKSAVE! (press F5) you can revert to this point by holding F9
8. Create a maneuver node about 135° clockwise of the current position of the Mün
9. Drag the prograde marker forward until the apoapsis on the dotted line intersects with the Mün's orbit. If you've done it right, a purple line will appearnext to it. If not, move the maneuver node (drag the grey circle) until it intercepts.
10. Turn your rocket until it's facing towards the purple marker on the navball.
11. Deploy solar panels!
12. Next to the navball, there is an estimated burn time. Warp forward until the time to the node is the same as the burn time, then throttle up.
13. When the green bar gets close to zero, cut thrust (x).
14. Delete the node. If there isn't a purple line on your trajectory, burn prograde until you get an intercept, unless it's really bad in which case reload your quicksave. If you did the transfer correctly, quicksave.
15. When you get into the Mün's gravity, burn retrograde at Mun Periapsis until you're in a circular orbit around it.
16. If you want to land,burn retrograde until you start dropping vertically. (if you just want to go back, skip to step 21)
17. Quicksave
18. Wait until you're a fair distance (it's hard to judge) above the surface, then burn retrograde until your velocity is about 50 m/s, then keep fallling. When you're very close to the surface get your velocity down to 10 m/s or less.
19. Frolic on the munar surface. You can jump in the air and press 'R' to fly about the surface using the suit's thrusters.
20. Get back into the capsule. Then throttle up, and get your apoapsis to about 7,000m, then burn either west or east (doesn't matter which)unti lyou're in a circular-ish orbit
21. create a maneuver node on the prograde side of the Mün (the way the mün is moving) and burn prograde until the purple dotted oval around Kerbin's periapsis disappears.
22. Wait until re-entry to jettison your fuel tank (it looks way cool), and deploy your parachute(s) at 10,000m or so.
23. Land and celebrate a safe return home!

TL;DR: Use maneuver nodes, don't take too much fuel, use small engines.