If you are currently on a Unix based system, do the following:
Open a terminal window. Then type in "lsblk" (if on a Linux), or "diskutil -list" (if on a Mac). Then, find your device (will most likely be something like /dev/sdb1). Remember that name. Make sure it isn't the sub name of the device (the current partition). Then, type: "dd if=/path/to/file.iso of=/dev/devicename bs=2048". Do bs=1024 if your computer sucks. Wait for it to finish. That's all there is to it!
If you happen to be on a Windows, download
this, install it, and do the following:
Type: "dd if=C:\path\to\.iso of=F:\ bs=2048". Replace "F" with whatever drive your USB stick is under "My Computer". Then wait for it to finish, and you're done!