What are the some good signs wich indicate if she is really interested in you?

Hi, most of time I can make out if any gals is building a soft corner for me. Her activities and way of speaking hints me that she is interested. Coz I have been noticing many girls in the college behaving differently and more responsively to me compared to other college guys. But the big Question Is she really liking me or just enjoy my company or likes me but doesn't wanna move ahead with me. Please help to determine the line which differentiates actual liking and just timpass behaviour among GIRLS.. And how should I take my move/step if even I have the same feelings for her.