So the most basic tip I can offer when it comes to queries for InfluxDB it is this.
Always qualify by time, yes, always.
InfluxDB is a time series database platform. They designed it for you to query by date. So fight the urge as much as you want to run a query that doesn’t qualify by time. Just don’t. Qualify on time. It could be a week or a month back, but make it easier on InfluxDB and qualify on time.