i'm a newbie when it comes to aquarium plants. Can someone tell me what I should be aware of when it comes to adding plants? Will the plants affect the water quality? Do I need to add any plant nutrients and will it affect the water?

okies, when adding plant you should always disinfect them first with a dilute solution of bleach, or pp. this is to endure that you dont egt any hitch-hikers or pathogens passed into your tank
As for nutrients, you should certainly use some sort of trace element replenisher, and good lighting is essential. In tanks more than 18" deep, you will need to use T5 lighting.

whats pp??

PP is purple Potassium Permanganate crystals. Check hardware stores in the water department, or look into ordering online. I couldn't find it anywhere, but my mom's a chemestry proffessor so she brought me a bit. Its really the best thing to disinfect plants with since it is gentler on them, but still kills parasites and pest snails. You only need a tiny tiny bit also.