Unravelling, to start. An imbuer's best friend is a treasurehunter. With a treasurehunter you will be getting loads and loads of low-level crap magic items, which you can hand over to your imbuer en masse.
Keep a chest full of the items you are not powerful enough to unravel. Soon you'll get a feel for your range -- low level rings are usually the easiest to work with.
Note that this will only work to a point. Once you start to get to the 70s (maybe sooner) you are going to have to craft items to get any decent advancement.