It is not within normal culture to tip in Uganda but where Western clients often frequent it is often expected. Employees at lodges and restaurants are always appreciative and you will often be quite overwhelmed by the reaction of those you have tipped. Guides and drivers who spend several days with you should always be tipped based upon the service they have offered to you. They will rely upon tips to make up their wages so insisting upon good service for a good tip is always a good idea! Somewhere in the region on 10% can be a good guide to tipping.