This should be free of extraneous smells, like fresh paint, cooking, smoke or floor polish. It should also be well enough lit for you to be able to consider the appearance of the samples presented. Some people prefer to be seated at a table but many expert blenders, who have to nose large numbers of samples, and who know what they are looking for, do it standing - even 'on the run'.
Tasting in company and comparing notes is much more useful than nosing alone, as well as being more fun. Alone, it is easy to become manacled by related descriptors. The comments of other members of the panel can break this pattern and set you off into new areas of exploration.
For serious tastings, the room should be quiet and well ventilated. Panel members should not wear perfume and should not wash their hands in strong-smelling soap immediately prior to a tasting. They should not have eaten a large meal before the tasting - the senses are sharpened by hunger. Most people are at their best from a sensory point of view in the morning, before lunch. At important tastings, the glasses should be washed with odour-free detergent and allowed to drain dry before use, since even polishing with a cloth might leave a trace of scent.