ideally with flat pedals installed, ride slowly up a very steep hill. middle ring, largest cassette cog is ideal. pull up hard with both a strong pedal stroke & your arms. pick a point in the distance & focus on it, this will help your balance. at all times cover the back brake. for people who’ve mastered wheelies you’ll notice them feathering the back brake to ensure you dont over rotate & fall off the back.
in 1992 I didnt think I’d ever be able to wheelie, its just a matter of putting the time in to practise.
with further practise one handers, rolling non footers & even non hander wheelies are all possible.