So lately I've been listening to some emo/screamo music, or whatever genre it is. Mostly bands like Saetia and Orchid. I have become very interested in this style of music and would like to try my hand at writing a few songs. I've noticed that many songs in this style are rather dark and sincere.

Im just wondering what kind of skills and/or knowledge I should focus on in order to possibly write in this manner. Can anybody help me out if its not much trouble? I hope my question doesn't seem ignorant. Hopefully somebody is familar with the writing style I am talking about. Thanks in advance.
Why pluck just one string when you can...

I haven't listened to a lot of screamo, it's not my favorite genre at all. I've tried a few orchid songs and from the sound of it I can guess they're using minor scales. so try with minor riffing, with maybe a touch of HC punk.
Write when you're not happy. Find some issue that's bothering you, making you sad, or whatever, then personify it. Find different ways to illustrate that feeling it gives you. Melodrama can be used effectively, but you have to keep it in check so it's not off putting and over the top.

Venus and Bacchus is animated, poetic, and very dark, so take a look at those lyrics and think of how you can write in that vain, then pull away and make it your own.