how do you tell a guy when your walking on thin ice

theres this guy i really like.... we used to be really close... we drifted apart.... now we're getting close again....he used to have a huge crush on me... then i think he went off me (when we drifted apart) and now i have a huge crush on him.... should i tell him... when things are so unstable.... hes a sensitive guy and i don't want to pressure him... cos he is such a great mate.....

if i should tell him... how should i?

what should i say? and how should i say it?

and what are the signs that he likes me bak? what should i look out for?