Sentire is like "to hear". You can hear someone even without wanting to. Ascoltare, on the other hand, is like listening. You can hear people talking in the steet without even paying attention, but ascoltare is something you do on purpose, you listen to (ascoltare) someone who is talking to you. The same goes for vedere and guardare. Vedere is like to see, you can see/vedere people without even trying to but guardare, just like to look/watch is something you do on purpose. If you are talking on skype, for instance: can you hear me? = mi senti? (or riesci a sentirmi?) and can you see me? = mi vedi? (or riesci a vedermi?)

Ciao Ashley, Sentire vs Ascoltare
= Hearing vs Listening 
Vedere vs Guardare?
= Watching vs Looking 
If an Italian was going to have "Can you hear me?" or "Can you see me?" which would he say? When would you see the other one? Can you hear me: Mi senti? Can you see me: Mi vedi? It is a little more complicated when you’re using a sentence showing respect. But aside from that, you might consider: Can you hear me: you’re talking and you want to know if the other person can hear you. Can you see me: you’re wanting to know if the other person can see you. Mi ascolti: are you listening to me? Mi guardi: are you watching me?