Take a walk through the woods or a park. But this time, visit the library first. Choose one or two books about identification of plants. There will probably be several, so find one for your level. If you're a beginner, try to get a book that guides you through step-by-step. They are called "taxonomy guides" and are available for all types of plants.
My first college course was Botany. I took it the same summer I graduated from high school. I think the teacher wasn't quite as enthusiastic as he could have been, but we did get through all the material. The best part, however, was that he didn't want to be in the classroom on those beautiful summer days anymore than we did. So we would go for two hour walks through the amazing parks we have in our city. One is an arboretum that lends itself perfectly to this kind of hand-on learning. I may not remember the vascular structure of a plant, but to this day I can still identify an amazing number of trees, flowers, and even weeds.