Girls do let out signs of liking a guy and for that matter also disliking and shunning a guy.
You'll surely be able to gauge, but only if you're intent on analyzing the signs..
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She engages in conversation with you- You meet a girl at a party and you exchange cell numbers and addresses and other information of where you study or work.
May be you also exchange information on your mode of traveling to and fro to your college or workplace.
Do discuss her and your hobbies and interests.
Maybe this is your first and last chance until you know she likes you and will meet you again.
Her response to you is indication that she likes you enough to continue to speak with you.
She responds to meeting you- It's a guy's duty to get in touch first.
So just call her up the next day at an appropriate time when it would not disturb or interrupt her work.
Tell her you enjoyed meeting her and talking to her and would definitely like to meet her again.
Her response may be in the affirmative, and well if it's not then call her again after two days and propose picking her up after work to chat over coffee.
If she has liked you and enjoyed your company she will definitely accept your invitation.
Remaining in touch- Her behavior with you will tell you that she has liked you enough to keep in touch with you hereafter.
She will find an excuse to get in touch with you to thank you for the coffee and a wonderful evening.
Respond to her with the same fervor and tell her that you too enjoyed the evening and that you would like to continue to see her in the future.
Her relaxed way of talking with you will be a sure sign of her liking you enough to meet you more often.
Now it's entirely up to you to maintain the contact and take it further from there.