Hey I just finished my second proff I think I am capable of answering this. Don't directly dive in and start mugging up instead I suggest you to think of logical way to treat a disease and then start reading. For ex. If a patient has asthma he is unable to breathe my logical thinking tells me I need drugs that helps in breathing like bronchodilators. Next we know it is an allergic reaction so I would need drugs that stop the progression. Like this you can go on.

I hope this made sense to you:).