Scotland doesn't have fixed rules for tipping, something which can make it more difficult for visitors to know how to respond in different circumstances. There are three scenarios in which the question of tipping arises in Scotland: in restaurants, in taxis and in very upmarket hotels. Tipping is not usual in pubs, though especially good service might be recognised by the offer of a drink, which you then pay for on the assumption the member of staff will have the drink at a quiet moment or at the end of their shift.
Some restaurants include a service charge of 10-15% in the bill, in which case no further tip is needed. If a service charge is not included in the bill, then it is normal to add a 10-15% tip if the service has been good. If you are paying the bill by credit card, you should either leave the tip as cash or, if offered the option, add it onto the bill. Restaurant staff tend to prefer tips left in cash: restaurant owners tend to prefer them left as credit card add-ons to the bill.
It is normal in Scotland to give taxi drivers a tip of about 10%. We've seen it suggested that it's less usual to tip minicab drivers, the type of taxis that you can only book by phone rather than find at a taxi rank or flag down in the street: but in practice this is a fairly subtle distinction for most visitors.
The last area in which the question of tipping arises is in relation to staff such as porters and waiters in very upmarket hotels, especially in cities. On the whole, we suspect that if you are in the habit of using such hotels, you really don't need our advice on how to tip in them!