I chose to not previously respond to this because I think a lot of "common things" that I "look for in a little/submissive" can vary based on the personality of the person I am talking with or connecting to here. A lot of things are situational based too. Like, I'm going to say I like a non-bratty little but a little fussy whine when he/she is sleepy can be very cute.
I'll try to be extremely generic though to try to cover only the main points...
I would say that I look for general non-bratty attitudes. I like a little who is easily compliant and doesn't argue or fuss much. I'm not attracted to those who like to test my dominance or fight me over it to force them into some form of submission.
I would say I look for compatibility outside of being just a Caregiver and just a little. I feel like it's very important to connect over other means and find happiness in other areas of enjoying each other. Littles who only want to be little and never, ever have an adult/intellectual conversation with me kind of turn me away.
I look for littles that don't fib. I don't like liars and I feel like if you're lying to me about something simple then you're probably lying to me about important things too.
I rather enjoy littles who are often little in various ways and can flex in and out of being fully little and just being generally childish. Perhaps they regularly do enjoy cartoon films or regularly do relax by coloring while they have a full on discussion about biology. If you're more a "24/7 little" in personality then my interest rises because deep down inside that's who I want.
I look for a physically intimate match as well. I'm an adult woman with adult needs. I don't identify as asexual and wouldn't connect well in the long run if my partner never had those desires. If we share a physically intimate kink then that's something that we'll both have fulfilled by each other. In the same regard, being overly or constantly physically intimate will back me away.
AB attracts me. I suppose this might be one of my more firmer, nonflexible desires overall. An adult who can wear a diaper and enjoy it is great because, for me, it adds so much to the caring experience.
I prefer littles who are needy and clingy but not pushy or demanding. I like being in charge, making the final decisions, and being followed in those decisions. Demanding I do things or pressuring me to do something feels manipulative and unhappy for me so I tend to lose interest when I feel that is happening. Want me, need me, rely on me, and show me that you think of me often but please don't make decisions without me just because it's easy.
I suppose that falls into a bit of patience, too, because, "If Mommy says wait then you quietly wait for Mommy." I think that's probably the hardest things I've ever encountered though because patience is something to be practiced and learned.
I'm going to stop here. I feel like listing off things like we're at Subway ("Yeah, I want a chicken breast on wheat with provolone cheese, a little extra olives, onions, and just a little lettuce.") feels pretty wrong and degrading and I'm not sure how else to respond with real, actual answers and not some generic form. I think my point is, I like a person and know that none of us are perfect so I don't expect that. My list of "this would be nice" is quite flexible in many, many ways.
Just know that in the end we are all different. We all want different things. We all enjoy different aspects of each other. There is a match to you. There is a match to every person. You are perfectly you, exactly how and who you are in this very moment.