Get out at least once a week and identify plants. If you don't do this, you will just get into a self defeating cycle of learning things and then forgetting them. When you get out fairly often, your knowledge will grow.
When you learn a new plant, pay attention to the family it belongs to. After a while you will start to see patterns and then when you run into a new plant you will often know right away what family it belongs to. If you have good book organized by families, this will take you to a short list of candidates. Many books are organized by flower color, which is fine if you are entirely lost or a beginner. Once you recognize families you start to see some order and organization instead of learning hundreds of unrelated individuals.
Don't be scared of scientific names. You can ignore them if you want. One problem is that the scientists are currently in a fit of reorganizing and renaming things. You used to hear that the scientific name was unambiguous, but that is no longer true -- in fact the popular name may have more stability than the scientific names these days. This is frustrating, but there is not much that can be done about it. Many plants these days have at least three names. The popular name, the old scientific name, and the shiny new latest scientific name. You can be snobby and berate people if they don't use the latest scientific name.
Tom's Plant pages / tom@mmto.org