I would suggest starting with The Vocation of Man, which is short and clearly written. If you wish to go on to The Science of Knowledge, I'd suggest reading up

I would suggest starting with The Vocation of Man, which is short and clearly written. If you wish to go on to The Science of Knowledge, I'd suggest reading up on Kant, and perhaps some Schelling: I found Fichte a lot less opaque after reading a couple of short volumes of Schelling. It has been a while since I read it, but it seems to me that Paul Beiser's account of Fichte in German Idealism: The Struggle Against Subjectivism, 1781-1801 was worth reading. [Edit: added inadvertently omitted "you".]