The others are so right about compliance. You don't really need any other "signs." You can test compliance at several levels.
My very first test of a woman is usually the lingering handshake test. This is something I usually do on a first meet, and only if the vibe is initially good. Or in general, if the vibe is good, I might do it, just for the commonality and bond it creates. It goes something like this.
You go "Heeyyyy girl long time" (big smile, if you know her, often in conjunction with a nice, long and soft full-body hug), or "Heeey you're someone I wanna meet!" (if cold approach, not necessarily those words exactly but that vibe). Then offer your hand for a shake at the introduction. Normally, when people are done shaking hands, you release the hand completely. This is the social thing to do in a platonic relationship. Except you're not going for that. You're going for the sexual/romantic take, so instead of letting go, simply loosen the grip. Ease off, but don't let go. Then keep holding eye contact and speak magic mutterings of seduction. And check what she does. Does she keep holding onto your hand? Great sign! Does she pull the hand to herself quick? Ouch. Probably back off a bit yourself. She's not comfortable (and may never be).
Her holding onto your hand is a form of compliance. Perhaps she'll even cuddle your hand. Then escalate fast, cuz she wants it.
I use hand-holding a lot to get compliance. Say you're on a date, or just hanging out, and you want to cross the street. Take her hand first, and lead her over. My gawd what a gentleman!
At the museum, or idk you living room or idk anywhere and you want to show her "something" (it's just an excuse to...): Take her hand and lead her to whatever you want to show her. Hell, make something up so you can lead her there to show her whatever. The point isn't what you're "showing" her, but to test compliance.
Other stuff you can do while talking, is to subtly make her move one or two steps this or that way. "Hey c'mere" then gently place your hand on her waist and move her a bit. Say out of the way of people passing by during day game. Or lead her closer to a chair you want her to sit down at, and so on. Abuse this all the way!
Baby-step it first, then make bigger asks. "Hey, I'm hot. Let's go outside a bit for some fresh air." (For you smokers, this is a golden opportunity to take her outside for a smoke... And a makeout. If it's cold outside, even better, enter your excuse to "keep her warm" by hugging her close....) Next up: Hey, I'm hungry. Let's get something to eat. It's just around the corner! (And by that you of course mean 45 minutes out of town to a small Italian place just outside your pad....) Baby step it. First one, then the other and "Omg this just nearby my place, I have the most amazing whatever I wanna show you (classic here is a stamp collection) come up and see!" Again... Take her... Yeah, what was the go-to think to take here? Aha, good little primary school pupil: It's of course her hand. Grab her hand and go! (Sorry for being condescending, but admit it, you thought it was a bit funny.)