easiest way to grow lavender?

Drainage is the whole game with lavender. It wants full sun, poor-ish soil and no wet feet - in heavy clay it'll sulk and rot over winter, so plant on a mound or in a pot with plenty of grit. Don't feed it much. After flowering, trim it back by about a third, but never cut into the bare brown wood, it rarely regrows from there. Buying small plants is far easier than seed.