My own set of heuristics

1. Use less subagents. The act of using subagent already needs dumping adequate amount of context for subagent to work effectively

2. Refactor when file grows large. Reasonably scoped files is easier to understand, for both human and agents, and consume less tokens because less guessing which section of the file to read

3. More capable models for planning, learning. Cheap models for execution. Same for human teams, senior member for higher level planning while junior member more on the act of translation of idea into code

4. I wasn't doing any fancy stuff that opus can't handle

5. Consult a second opinion for things you are not sure. (I have made a skill specifically for that)

6. Audit how your habit correlates with token consumption. I found out a skill a use frequently is using a lot of context just so a subagent can get all the context. (made a tool to audit claude specifically)