The right equipment in the studio is the equipment that will get the results you are looking for. If an old but reliable microphone gives a warm sound that the musicians like, then a more expensive microphone is not necessary. The same applies to the musical equipment being used by the musicians. If it gives the sound that the musician wants, then it is the right equipment.
Separating sounds makes it easier to mix and master the recording later. Some engineers prefer to record the rhythm section together and then lay everything else on top of those tracks. Once again, it depends on the sound you are trying to get. But recording tracks in different rooms, or at different times, can make the final product easier to control.
The musicians and the producer need to know the music before entering the studio. Pre-production is the process of recording demos of the songs and then working through the demos to get to the final product. These recordings are traditionally done in home studios or smaller, less expensive studios. By the time the recording begins in the large, professional studio, everyone needs to know what to expect.
Setting microphone is critical to getting a good sound. Do not be afraid to move microphones to many different parts of a room, or use multiple microphones for one instrument, to get the different sounds you are looking for.
If the musicians are used to recording the drums first and then the rest of the instruments, then that is the sequence to follow. Recording out of sequence can throw off a musician and result in a bad recording.
The musicians and the producer should get into the studio before starting up the recording devices to experiment with the studio equipment. That includes any special instruments that the studio has to offer, any effects on the recording equipment and any small rooms in the studio that could be used for recording purposes. Become familiar with the special features of the studio so they can be used to create a better recording.
Before you launch into your first take of a song, do a quick 30 second test of the equipment to make sure everything is working properly. Once the musicians get started, it can be distracting to have to constantly stop because something is not working right.
As you follow the proper recording sequence it is important to deal with each process one step at a time. Do not worry about moving on to mixing or mastering until all of the recording is done. Take the process one step at a time to be able to focus all of your attention on getting the right sound.
Effects such as delay and reverb can be added to a recording during the mixing process. The musicians should be allowed to get the precise sound they want out of their equipment, but the recording itself should be done without effects. It is much easier to add effects to a completed track than it is to try and remove them.
If the middle of the studio does not sound right and moving the microphones does not help, then try moving the musician around. Each studio is different, and each room in a studio has a different sound. Move around to find that sound you are looking for to get the best recording possible.