A great place to start with using herbs in diet is to look at ayurvedic "kitchen cures." Graduate to Vasant Lad's textbooks if you like a basic book on the topic. That way, you have some dietary tools for supporting constitutional health and working with people that have goals about specific aspects of their health.
There are some good herbal conferences out there. I try to go to Medicines From The Earth (near Asheville, NC) or Breitenbush (OR). I haven't been to the Southwest Conference but I hear it's amazing. The group that puts on Medicines and the Southwest conference have audios available from botanicalmedicine.org. That way, you can cherry pick topics of interest or areas where you need more growth.
For books, consider:
Herb, Nutrient, and Drug Interactions by Stargrove and Treasure (You'll need a reference. The Natural Medicines Comprehensive Database is way too conservative but is more comprehensive. I always trust Stargrove over it.)
The Mood Cure by Ross
Healing with Whole Foods by Pitchford
Medical Herbalism by Hoffman (for reference, not that you'll be practicing as an herbalist)
Nourishing Traditions by Fallon
Encyclopedia of Healing foods by Murray
When the Body Says no by Mate
The audiocourse from Bergner on insulin resistance is helpful Herbal Education -- Beginning, Advanced, Clinical, Classroom, DistanceYou may want to pick a specific area and do lots of study on that area for a year at a time. There are so many tools out there to learn about. It's better to really delve in deeply to one modality, get to know it for a year or two than it is to try to learn a little about everything and not have deep knowledge about any one thing.