When attempting, best to turn the front wheel a little to the left, and point your left pedal toward the front wheel (or both on right side if you prefer), like this example;
Keep moving back and forth until you start to get the hang of the balance.
Some people find it easier to practised on an upward slope.
Bear in mind a fair number of off the pegs singlespeed/fixed wheel bicycle have too high a gear to begin with, so if you struggle, might be worth putting a bigger cog on the rear (1 or 2t bigger).
Practise make perfect.
When attempting, best to turn the front wheel a little to the left, and point your left pedal toward the front wheel (or both on right side if you prefer), like this example;
Keep moving back and forth until you start to get the hang of the balance.
Some people find it easier to practised on an upward slope.