The way I will tell you how to do a wheelie and you being able to just go out and do it, and get it right after a while will all depend on how good you are at knowing and feeling what you can do with your bike.
 

   If you ride an R1 - CBR 900 – 1200 Bandit – etc, These types of bikes are the easiest of all for wheelies because they will wheelie off the throttle in first gear without trying hard at all.
 

There are different way's of doing them.
 

1: Riding off clutch all the way out doing around 20 – 30 mph shut the throttle then open it and pull on the bars these people usually don't change gear they rev the nuts of it and don't look in control.
 

2: Some others pull off usually from a traffic light as above and instead of shutting the throttle they just give it more gas and pull on the bars, This is a better way than above but still not right. You do not need to pull on the bars.
 

3: Others pull off and then pull the clutch in and out quickly " Slipping the clutch " This is only needed if your bike will not lift just off the throttle. Bikes " some 600s maybe some 750s, I say some because I have ridden the R6 Yamaha and new GSXR 750 and these will lift just from opening it up in first gear and letting the engine do the rest, But it will be harder than on the R1 etc as these have more torque " low down power " than the smaller bikes.

Wheelies on an R1, CBR900, 1200 Bandit etc:   First gear, pull away and let the clutch all the way out but try to keep two fingers on the lever,  (Some people may feel better with more or less fingers on the lever some may not use the clutch at all.  Use what you feel most comfortable with) This is if you want to progress and start changing gear and if you do you will do it all in this little one two step. So you have pulled away clutch out and two fingers on the clutch lever all in one go open the throttle fast enough and wide enough and the bike should pull away really quickly and if you are riding an R1 this should start to wheelie at about 6-7000 RPM and it will literally jump up very fast so be careful not to let it go too high too quickly, The Bandit will be the same but the Blade may start to come up around 7000 to 8000rpm and will not wheelie as quickly as the other two. Anyway back to the wheelie.

Gear Change:    When it comes up you need to change to 2nd gear as it comes off the pavement. Wait until it is say 2 feet off the ground. Do not try and blip the throttle a few times in first gear this is too aggressive the bike will be a lot easier to control in 2nd gear.  You should be able to ride it for a lot further than you could have done if you stuck to first gear.  Now, you are up in second.  Try to keep the throttle as smooth as possible while you are doing the wheelie.  Try not to keep blipping it. Instead, try to roll it on and off slowly.  To do this the bike will need to be up very high near the balance point where you will only need to give it very small amounts of throttle. You will need a lot of practice before you can wheelie this good but if you try hard enough and think about what you and the bike are doing.. You should get the feel for it soon enough. Remember to try and look where you are going when you are on one wheel, try to look either side of the bike or just make sure you are not going to hit something that you can not see !

MoreGears:    When you are getting to the end of second gear don't of let the bike rev it's nuts off and hit the limiter.  It will hit the floor quite hard and can easily burst fork seals. All you have to do is change gear again into 3rd . Again, most people who can already change gears do it by changing as fast as they can.  Sometimes it will stay up and they will ride it through 3rd as well.  To make it that little bit easier just before you change to 3rd give it a little extra blip on the throttle.  This will help the bike stay up easier because that change from 2nd to 3rd may be fast, but the bike will start to come down and you will have to give it more gas.  If you have not got the wheelie high enough it will go down.  So, try to blip it quickly as I said and this will help a lot when you get it right.

600-750cc Bike's:    This is nearly the same as with the other bikes, except you will probably need to use the clutch more to get it up.  I said earlier on that some 600s will wheelie off the power without slipping the clutch at all.  I know the R6 Yamaha will, and I believe the new CBR600 will also. The other new 600s should do the same but I have not ridden these. The new 750s will do the same but older bikes may not.  The only difference is the use of the clutch and more balance to keep it up for longer as you will not have the torque or power as the R1s etc.
 

Power Curve:    When you pull off you should try and notice when your bike gives the most power but not top end power when it is running out of revs. Halfway through the rev range you should feel this. Maybe 5 - 7000 rpm when it gets to this, you will need to slip the clutch but very lightly. What I mean is, do not open the throttle get to 5-6000 revs and pull the clutch all the way to the bars and whack it back out again. That is not what I meant.  When it does reach 5-6000 just pull in the clutch lever enough so you hear the engine go to 7-7500 rpm and let it back out quickly but smoothly.  The rpm may differ on what bike you are riding but the rest is the same. Some people may like to whack the clutch in and out in 2nd gear to get it up. My way is safer and will not hurt the bike as much. To change from 1st to 2nd this is the same as the bigger bikes but is a little harder with less power.

  (If you get this far the rest is history.  You will be able to get 4th 5th and maybe even 6th if your bike has six gears. Always get the bars as straight as possible when it does come down and hold them as tight as you can to avoid a tank slapper.)

The Short Version:   Pull away, clutch all the way out,  give it a lot of throttle and it WILL wheelie, When it does change gear, don't try at all to keep it in first for a bit just change gear straight away when it first comes up to 2nd gear then get it higher and keep it up longer with easy smooth throttle actions ride it through 2nd and when you feel it needs another gear give it the little extra blip and go for 3rd as quickly as you can, the same for the rest of the gears.
 

Enjoy and be safe.