Perhaps the most popular is to advertise in the local paper. It is usual to include in the advert a general description of the business, its location and the annual turnover figure. Some give the reason why the owner is selling. Often the advert will give the phone number of the seller's accountant and wording to the effect that further details may be obtained from the accountant. This is probably better than giving one's own phone number.
Some advertisers ask people to reply to a box number.
This is probably the least desirable course of action. You should also remember the trade press when advertising. Often this brings better results than the local paper. Almost every occupation has its trade press. If your business is specialised and needs skill to operate it, then you should advertise in the trade press.