A very obvious one when he takes interests in your matters like work
schedule, it means he is really concerned with you and loves you. 

Whenever a guy keeps a track on your habits, remembers whatever you
do and say simply indicates his love for you. 

When a guy wants to spend more time with you, dates out with you at
places of your choice and shares your favorite pastimes then he
is madly in love with you. 

If he gives more importance to his friends even if you are sick or in need
of him shows his lack of interest in you.

Changing of topic when you discuss about your future with him is not a good
sign of a healthy relationship with your love. 

If he doesn't want to spend time with you or don't ever want to go out with 
you in public and never introduces you to his friends mean he does not love you. 

When he calls you or messages you just to chitchat with you means he deeply
loves you and was finding any reason to talk to you. 

If he is really concerned about you and loves you then he would always take
out time from his busy schedule. 

When he keeps looking at you when you are around and suddenly takes off his 
eyes when you look at him shows he is in love with you. 

When he praises about you to his friends, family and others means
he truly loves you. 

His every action will make you believe he loves you. 

If he changes his plans or cancels them last minute then he is surely avoiding you. 

If he is trying to be friendly with you and tries to make an effort
to know more about you shows signs of love for you. 

You can make out from a person's eyes. The person in love with you has
special shine in his eyes when he is talking to you

but A girl never keeps track of this so who knows....

not all girls r same
some girls do

Um yeah