One way I gauge interest is to plan things we can do together a couple weekends in a row. So on that first date i'll make a suggestion about next weekend. Maybe mention something mid week to prepare her like letting her know I was thinking of actually doing what we briefly talked about last weekend. Pick something that is not too pricey just to make sure she's not going just to do something free or whatever.
I make sure I am not being too pushy, just mention stuff and see if she brings it up herself later. This allows me to see exactly where I fall in her life. What I expect is some degree of interest in spending time together alone. This also lets you see if she is committed somewhere else. If she says she can't go, the reason she may provide you can use to find out where you stand. After that let her suggest a place, if she just doesn't then that tells you something right there. Kinda like creating a situation to see how she reacts.
Typically I do not like to ask a girl out two weekends in a row like that. But I use this to see if that initial attraction is there. Kind of a go hard or chill test. Some girls like to get to know you, some girls lose interest fast. Some girls will go out with you for a free meal and to burn a boring night.
With this test you can force that girl in front of you into the thought process of deciding if you are good to spend time with or not. You can look at her face, listen to the pitch of her voice and see if she is really excited or not. And if you are slick about it you don't even have to technically ask her out. Just kinda suggest stuff, if she's not biting stop right there and save face.
