If you are going to be recording other artists, developing some
studio practices is a good idea. A subtle, but necessary, best-practice
is to post a Studio Policy somewhere near the work area. It relieves you
from having to recite the 'rules' every time you record. It may also be
wise to put in the Studio Policy that you don't provide meals, drinks,
or overnight quarters for clients. It may also be important to include a
clause that allows you to stop a session in progress for any reason,
including musicians who don't know their parts, have bad attitudes, or
your having to try to record a musician who is intoxicated enough to
inhibit their playing.
Be as diplomatic as you possibly can be with clients. This is because at some point, you'll undoubtedly be faced with a client who you feel needs to change their sound. This is touchy ground with some people, because they feel you're saying they sound bad. For this reason, it's always better to be careful with how you approach them. Try saying things along the lines of "I don't want to interfere with (whatever is causing the issue), but I feel that the recording and the song are going to sound better if you do 'X'. Can we try it and see if you like it?" This will come off sounding more reasonable than simply saying you think they sound out of tune.
As the producer for your studio, you'll have to make important decisions that help shape the final outcome of each project. It's also your job to make sure that everything works smoothly with any booking, billing and record keeping.
Create written agreements for the various project productions you may encounter.