Though it's a myth that analogue systems are inherently higher quality than digital, they tend to have a distinctive sound that may work for you. This colouration consists of subtle distortions introduced by the circuitry. Let your ears be your guide.
With digital equipment you get a good idea of what the unit will do from its specifications. But if you’ve chosen the analogue route you need to be sure you like the sound of the equipment. Tape deck quality can vary enormously, and mixing desks are a world of their own.
Signal levels and gain structure are very important in analogue systems. With every channel open on an analogue desk you are increasing the ‘noise floor’ of a mix. Therefore it’s important that your audio is recorded at a relatively high volume (see Headroom).
In the glory days of analogue studios, an important role of the assistant engineer was to regularly ‘degauss’ the tape heads, removing residual magnetism that the deck acquired over the course of the session. Without this routine, the tape deck would quickly become unusable. So, if you’re intending to run an analogue style studio it’s important that you have a maintenance schedule. Clean your equipment regularly.
Finally, archive your work carefully. Magnetic tape is fragile, so make sure you store it somewhere dry and free from magnetic fields, such as produced by a fridge! Make multiple copies of your work, possibly even onto a digital format for the day disaster strikes.