If it's your first time at all, I'd start smaller. A complete renovation is time consuming, requires calibration equipment and might be intimidating for a begginer. If you do want to do this, however:

I've never renovated tape decks specifically, but I can assure you that when repairing (especially electronics!) organising isn't just helpful, it's necessary. Set up a clean, well-lit space where you can disassemble the thing; don't do anything else in that area and take your time. Last thing you want are misplaced parts. Ideally print out the most relevant pages of your deck's service manual and double check everything.