There are a few good, time-tested ways to learn vocabulary. Different students have different learning styles, so try a few different approaches to see what works best for you.
Straight memorization: The old-fashioned method is just plain rote memorization. It's dull at best, tedious at worst, not to mention the fact that the words gained tend to be so isolated that they can be unintelligible when they appear in sentences.
Flash cards: Modern life is a game of hurry up and wait. Here's something to do during those waits. Draw and quarter some 3″ × 5″ index cards. On each little card write Latin on one side and English on the other. (Use pencil; ink bleeds through and makes it easier to cheat!) Keep a little stack in your pocket, and pull them out to quiz yourself many times a day. Make your self-inflicted pop quizzes quick and keep them to no more than a few minutes. Remember to go back and review the old ones now and then.
Steno pad: Steno pads are great because they're ruled right down the middle. On the left side write Latin, on the right, English. Compile your list only from exercises. (It helps to remember things in context.) Take a 3″ × 5″ index card, and, starting at the top of a pad page, quiz yourself. Whatever you don't remember goes on the next line on the card. When the card is full, stop and keep the card in your pocket for the day. If you make it down a whole pad page correctly, put a tick at the top of that page. Five ticks up top and that page is a goner. Move on to the next.
Look it up: As you do exercises or read, look up every word you can't remember either in the back of this book or in a dictionary. The more important words will keep reappearing. The less important words won't. Eventually you won't have to look up those high-frequency words anymore.
Several studies on language learning have found that while the brain enjoys the stimulation of learning new things, it can also get saturated. This is especially true with studying vocabulary. To keep from spinning your wheels, keep your sessions working with this book limited to about half an hour. Several short sessions stick better than a few long ones.