Lilies are among the most beautiful plants for any garden, and they are much easier to grow than most gardeners think. The essential requirement for successful cultivation of all but a few species is well drained soil, but you will need to know whether any lily that you wish to grow is a woodlander, in which case a soil with a good proportion of organic matter and some protection from hot summer sun is advisable in most climates, or an open-ground plant which will require a less organically-enriched soil and will revel in full sunshine in all but the hottest climates.
The most likely problem in growing lilies is virus diseases spread by sap-feeding insects, principally aphids. Many bought-in lily bulbs carry viruses, indicated when in growth by a range of symptoms including poor growth, deformity and/or longitudinal striping of the leaves, deformed flowers. Such plants should be removed and burnt, not put on the compost heap, but unfortunately healthy lilies growing nearby are likely to have been infected before you notice the symptoms. It is better, therefore, to grow your lilies from seed, which is very unlikely to be infected with viruses, although there is always the possibility of your virus-free plants becoming infested with aphids carrying viruses from elsewhere, so vigilance is essential. You may wish to take preventative action by regular spraying with insecticides, but I find this tedious and prefer manual removal of any aphids that I see and roguing of any obviously virused plants at the first sign of infection.
The picture here shows Lilium mackliniae described in another plant portrait.