"As for tea. Would any herbal tea do the trick? I bought some this month that I haven't tried yet. I just got sick of coffee, and so figured I'd buy tea instead. I can't even remember what kind it is without looking, though."

On the concentration front; coffee and tea dehydrate you which deprives your brain of the fluids it needs to employ efficient cognitive function. I'm not saying don't drink any tea. A good herbal tea helps calm the nerves but also keep a water bottle next to you so you can take sips every 5 minutes to keep your focus on what you are studying. This steady consumption of water also helps out with pacing your study sessions using bathroom breaks to allow you to get up and clear your head for a couple of minutes every 45 minutes or so.

Also when studying make sure that you are facing a wall and that no open spaces in which people are walking occupy your peripherals as this will constantly draw your attention away from your work.