I would advise to to be able to 50-50, 5-0, ollie to nose manual, and nose manual shove-it out (for better balance). This trick is so cool looking and it shouldn't take you more than a week or two to land if you can do the tricks I have listed above.
You can do this Frontside or Backside, whatever feels more comfortable to you.

Just starting Nosegrinds
Be able to do those basic grinds on at least a 10 inch box because that is the smallest you will need to learn these. Ride toward the box at very little of an angle and be sure that when you land on it you will have 3 or 4 feet to grind. When you ollie you have to think of it as jumping off your back foot and land on the box with your front foot. Do that a few times (without the board). Now ride kinda slow and ollie up into a nose stall. Be sure not to let the nose touch the box because you will stick. Get to where you can to the nose stall for a second or two. After that you will be ready to actually grind.
Being able to grind and come off
Go for one of them nosegrind stalls but ride faster (as fast as you would need to do a 5-0). Ollie up and land on the nose. Now kinda tweak the board so that the tail points toward the middle of the box a little (about 10 or 15 degrees). Keep your body in the middle of your board with your shoulders paralell with the edge. Practice this non stop until you can grind to the end of the box almost everytime.
Comming out of the Nosegrind
The easiest way to come out of a Nosegrind is to put the back truck down when the nose is just a couple inches from the end of the box and to a little manual out. That isn't the coolest way to do but you will need to learn that way first. You can also ride off the end of the box and let the back truck hit the end to level you out. Do that by pushing your front let out straight and pushing the end of the board down. It's almost like a Nosegrind to 5-0 but you just tap the end with a very small 5-0.

Practice, practice, practice and you will get this trick wired in just a few weeks.