But Trumpets, Orientals, and Asiatics are a good starting point from a knowledge base stand point because most modern day commercially available lilies are hybrids based on those three groups. From there you can easily expand your knowledge a little at a time by association because almost everything you're going to run into today will have the word Trumpet, Oriental, or Asiatic in it somehere in the description.
From there and along the way, you'll pick up little pointers here and there like:
The Trumpet group is generally thought of as the most fragrant group, tall and that make good long stem cuttings.
The Asiatic group is thought of as the most colorfull group and earliest to bloom but generally not fragrant.
The Oriental group is thought of as the late blooming group with lush foliage and fragrance.
You'll pick up other little pointers too, like: lilies prefer a sandy, loamy type soil somewhat high in organic matter that has good drainage (lilies don't like wet feet). They withstand dry periods well. They never really go truely dormant but require a rest period called a chill (winter season) to produce a high bud or flower count the following year. Avoid using fresh animal manure as a sourse of organic matter. All kinds of little pointers, and you'll find it all here as we move along throughout the seasons.
We would be delighted to hear your comments and suggustions as we move along as well; and not necessarily limited to lilies either. Many of us grow a variety of flowers in beautifull garden arrangement settings so we always like to know 'what goes good with what'. For us, lillies are just central to it all.