You can use a flash drive or an ext. USB device like a CD/DVD drive or even a HD(AC powered?). That all depends on your needs but a decent brand 16gb flash drive will work fine for most and simple to use. As Kees already stated to you, just copy to the flash drive will work. Verify you have copied your files/folders and proceed to your normal usage. I like ext. CD/DVD because if done correctly will have a more reliable copy as flash and HD drives can get wonky.
Browsers favorites usually have export/import ability, find yours and do that, export to a folder/file and then copy that to your storage media as explained above. If you need a more constant update of your important data, look into "sync s/w" which can dump on demand or time frame data ID'ed by you. Also, ext. HD when brought in "full retail form" usually have s/w that back-ups, syncs or make it easy to save data to it.
if your important data is that critical and you really want to save then make "multiple copies" don't rely on one copy, things do happen as these forums post all the time.
tada -----Willy 