just look for the body language...

for my case example:

for the first few dates, when we sit beside each other, i notice her body is leaning toward my side, but havent touch each other... during movie also, got lean toward my side abit, but not fully lean ... so eventually during movie that time, i use some lame excuse to grab her hand, and she didnt resist, so ta da... officially can hold her hand liao..

if she is not interested, her body will not lean ( aka trying to be close with you one ), and will keep a distance such as sit upright, wont lean to your direction...

thats my experience lah.