A static balance can be very accurate, but it's greatly dependant on the skill, and patience, of the operator of course. It's also very important that the bearings of the balancer are as free as is possible of any drag, I sincerely doubt that you'd ever accurately balance a wheel when suspended upon it's own bearings, all balancers turn the wheel assembly complete on bearings that are specified for the purpose, and that have no seals as they will cause friction and lessen accuracy.
However, static balance takes no account of the axial displacement of the imbalance, as bike wheels have got wider this has become more and more important, nine times out of ten just sticking the balance in the centre of the wheel rim is fine, but not always.

Take the wheel to a reputable shop, it's by far the most likely way of getting the wheel suitably balanced. The balance machine will usually be set to measure in units of five grammes, however many of them can be set to measure down to one gramme, if you're feeling fussy you could ask the fitter to balance the wheel to the closer figure*.


*But expect to be told to **** off though.

Taken from Michelin:

To balance the wheel, your mechanic will use a balancing machine to determine where the heavy spots are. Weights are then attached to the exterior or interior of the wheel to counteract centrifugal forces acting on the heavy areas when the wheel is turning. This will eliminate vertical bouncing (static balance) and side-to-side wobble (dynamic balance).

I can see how a balance machine will fix vertical bouncing, but wouldn't it need to be driven to work out side to side wobble?

John Coopers in Derby still does it this way never had a problem off them.

If you let the wheel drop towards the heaviest point when friction of the bearings is a factor, the wheel will stop before if gets to the heaviest point. Since the friction should be the same either way you spin the wheel, if you let the wheel drop towards the heaviest point in both clockwise and anti-clockwise direction, the heavist point should be in the middle.

I imagine :)

Also, if you get the weight an inch or two out I seriously doubt you'll notice it. I knocked the weights off my back wheel by accidentally turning it with the caliper hanging off, and do you think I could tell?

Disclaimer: Despite this opinion, I still get my wheels balanced professionally. I can't fit a tyre myself and it costs practically nothing to have it done.