So there is this one rule which states that if "We have a feeling for someone we should tell her immediately rather waiting for the right moment and wasting time".

There is this other tactics or rule which is something like "One should never express his feelings towards a girl untill and unless he's really sure that the same feeling will be reciprocated because in doing so he will loose the mystery and as soon as the girl figures out him ,she will loose interest and will walk away"

They both sound equally good to me and also contradicts each other. Can anyone with great experience in this field explain which one of these rules or tactics should a guy follow in order to be able to seduce someone and attracts them?!