I would suggest working, at least at first, on Bochs or some other virtual machine the reason being that you can take it with you wherever you want, it's easier to debug (you can see the exact state of the hardware), and if you need outside help debugging they can use the exact same 'hardware' as you.
The most useful advice I have is to get yourself into a state where you can be running C code as quickly as possible -- i.e. boot up, setup your descriptor tables, and get yourself to a point where it's safe to run compiled C. Most if not all the kernel should be in C if you want to stay sane and keep working on it. Assembly, while required in some places, is tedious and tends to be hard to debug.
