My main characters (those at lvl 60 of which there are 8) all do admiralty missions (Klingon and Ferrengi). When you reach the 10th tour of duty you get 30k dill. These characters als farm events for dill (usually the 14 day ones where they get 50k dill). Finally, should they be really low then the go to Dyson and do some very easy dill farming (collecting elite marks and normal, which can be exchanged through the rep system for dill.
This works for my and is part of my long term strategy.