Cross-town travel;
Integrated scheduling (meeting trains and other buses/long-distance coaches);
Frequency and capacity (inc not cancelling services without notice);
Priority at junctions;
Customer service (not driving away when there are people running down the road to try and catch the bus), letting people with mobility problems sit down before driving off;
driving style - too many aggressive drivers forgetting that their job is to drive their passengers safely to their destination - drivers delighting in driving fast through puddles and splashing pedestrians - driving far too close to cyclists;

In fairness, not all drivers are guilty of these sins, and many car drivers would do well to consider other people while driving too, but let's start with what we can influence first.