Pick-up an OTG-USB thumb drive $25 for 32GB. These have a micro USB port on one side and a standard USB port on the other side. These make transferring files faster and easier, in addition you can even play the files from that device. I use it with my Samsung S4- a lot faster transfer speed and less BS compared to going direct from the phone to the computer.
this is the one I got- but there are a bunch to choose from:
for the Nexus 7, you will have to purchase this app (Nexus media importer)though: