Beginner Gardening: Succulent help! Over-watered? , 1 by Joyka

Joyka wrote:
I recently bought a beautiful arrangement of succulents from a woman who sells them professionally (see attached photo). They really are gorgeous, and although I'm definitely still a beginner I've become very interested in succulents and was hoping to try propagating them as soon as possible.
I live in a college dorm, so my space and access to light is limited. My window gets indirect sunlight. I've noticed a few of my plants getting a bit leggy, and I assumed that this was the reason.
However, I have recently noticed that a few of my plants are turning yellow on the very lowest leaves, and some appear to be slightly deflated and mushy. None browned, yet.
I have done a good bit of reading on the internet and my guess is that I overwatered them. I was warned not to do this, and thought I was being careful, but I totally blanked on the fact that this lovely arrangement came in a ceramic container, with no drainage, so I am guessing I did indeed over-water them.
Obviously I will not water them again until I can be sure the soil really is dry, but I don't know if that will be enough to save them! Is there anything I can do?
Please advise me how I can save my poor over-watered plants, I don't want to lose them! :(