I used a tour company to help me with things I wasn't completely familiar with. In particular, I can highly recommend Inside Japan Tours, they were excellent. I hear their tour guides are great as well. I did a self guided tour without a guide, and all my hotel reservations and even park tickets were taken care of by them. There are certain things they can't do, but I would definitely go with them again if I were to go to a different country.
I'm not sure if I would use them again for Japan since I can understand Japanese decently and now have an idea of what to do in Japan. Studying Japanese and being in Japan are obviously different things, but their tour company did make everything much easier. Since I'm more familiar with the layout of Japan, I think it was nice not having to deal with an excessive amount of planning.
I'm not sure about just tour guides though, I'm sure you can check JapanTravel reddit for some recommendations.