How to add more words to my prose

This is a complaint that I get regularly, that some of the scenes I write are too short and come off a bit rushed. Usually I'm told I should add more descriptions, which isn't really my strong suit. To give an example, I recently wrote a scene where a couple gets into an argument. Said argument lasts less than 200 words (granted the argument gets interrupted when their friend shows up). Does anyone else have this problem and how do you get around it?

I've had this problem. What usually works is adding subtext into the conversation. Rather than the couple getting right into their argument, they instead talk about something else and it escalates to an argument. But writing subtext is really hard, especially if you never speak in subtext (like myself), so I'd reccomend looking up guides on how to write it.

Remember to bring in the environment. Use actions as well as plain dialogue tags, because if you don't remember where the characters ARE, you're going to end up with Talking Heads where the readers keep forgetting they're NOT in a featureless, soundproof room with nobody there but them.

That's something I've had to teach myself to do and I use the Character Development Threads to practise it.

Another thing I've taken to doing is to put motivations in; get inside the characters heads and see the situation from their side and show why they respond as they do - it's great for showing misunderstandings that lead to further conflict or what the characters Berserk Button is and why they went off like they did.

I was about to give an example but I ended up losing it so I'm going to say that I really empathize with you. I too really suck at trying to reach the required amount of words and pages for something to be considered a novel. It's a pretty daunting task. It's not all that helped that my sentences don't flow that well and I keep using the same phrases for prose. The sort of thing happens less frequently in my dialogue but I still struggle with it.

So how can you get better? Read many prose you can get your hands on. Observe day to day life and describe what's happening to the best of your ability. And, importantly, practice. Doesn't mean doing something over and over again but it helps in the long run.

I often have that problem, and I find it useful to write a draft and set it aside for a while. When I read it later and replay the scene in my mind, I can see what I've left out that I can add.