Tips are generally low in Turkey. You never tip on a credit card charge and if you tip in cash, leave it on the box which comes with the bill. No one gives hands-on tips!
You should tip in Turkish Liras, as it is the only accepted currency in shops, most restaurants, transports…
Airports/Train & Bus Stations
If you have someone helping you with the bags, a tip between 2-3TL per bag, should be enough
Taxis & Transfers
For taxi drivers, don't tip, just round the fare upwards to a convenient amount. If the fare is 19.50TL, round it up to 20TL. For private transfer services, no tip is required, though if you wish to tip, 5% to 10% of the fare is appropriate
Hotels
Porters are happy with 2-4TL per bag. In some hotel breakfast rooms, restaurants, and/or at the reception desk you may see a Tip Box. This is the appropriate place to express your appreciation to the staff for the good service
Restaurants
In inexpensive establishments, small tips (5% or so) are not necessary, but are appreciated. In luxury restaurants, tip 10% to 15%
Guided Tours
Tips to guides and drivers on organized tours are at your discretion. They are already being paid by a company to be your guide or you are already paying them for the tour
Turkish Bath (Hamam)
At the end of your bath, all the attendants (and there are lots of them) will line up to "bid you goodbye" and expect a tip (if service has been good). Share out among them about 10 to 15% of the total price of the services you've used
Dolmuş/Minibus
No tip expected