Since there are many types of phones and a plethora of items you may want to transfer, here are a few suggestions.
1) keep contacts in a place like google and just sync from there.
2) keep things you may want later in google, dropbox, cloud or other such location that you can reach from anywhere.
3) If you are updating your phone ask the person in your phone store for help.
4) If it's too late for that there is a little card (sim card or SD card) in your phone you can move over if the phones are compatible (I've never had much luck this way).
