Upvote:2
For the restaurant waiters, it is recommended that you leave the tip on your table just before leaving. It is common practice - Greeks do it too.
For the cleaning service, sometimes there is a special folder for tips. Generally speaking, cleaning service will prefer not to touch any money so as not to cause trouble. Therefore the best method is directly telling them that the tips are for them, or leaving a written note again specifically mentioning whom the money is for.
Upvote:6
If you want to make sure that the money goes directly to the people, give some cash to them directly. For the cleaning service, you could leave it in a conspicuous place in the room (with a note indicating that it is a tip). For the restaurant, you could leave it on the table (the way you normally leave a tip) or give it to the server directly.