Considerations
Plants are a great entry point into learning to appreciate the biodiversity around you. They are the base of most land ecosystems on the planet, and big bonus they don’t run away.
I recommend learning flowering plants at the family level. This will help you learn the general structure of flowers families that will apply at many different locations around the globe, and help you appreciate the truly amazing deviations from the typical structure.
Bonus geology and environment are big factors that cause plants to speciate. Finding unique geology is a good way to find some truly unique and beautiful plants.
Tools
There are many great guide books that can help you learn what plants you are looking at. Many guide books are organized by region or petal color.
Identification keys are different. They are more precise and technical comparing features of the plant that can help you identify exactly which species you have encountered.
A great light and compact magnifying glass that can help you get a closer look while enjoying the outdoors.