Every nonprofit has tried to fix its data and watched the effort die. The reason is almost always the same. The system asked already-stretched staff to do more work, on top of the real work, with no immediate payoff. So it slipped, then stopped.
Capture at the moment of service
The single biggest improvement is timing. Data captured at the moment your program actually happens is accurate and nearly free. Data reconstructed weeks later from memory is slow, wrong, and demoralizing. Build collection into the session, the intake, the visit, not into a separate reporting chore.
Collect less, on purpose
Most intake forms ask for far more than anyone will ever use. Every extra field is a tax on the person filling it out and a place for the system to break. Decide the few outcomes your funders care about, and collect only what proves those. You can always add later. You can rarely recover trust once staff decide the form is busywork.
One point person, one place
Scattered spreadsheets are not a system. Pick one place the data lives and one person responsible for its quality. That person does not have to collect everything. They have to make sure nothing important goes missing.
Protect the people in the data
Track outcomes against participant identifiers, not names, and minimize sensitive data by design. This is both an ethical obligation and, increasingly, a funder requirement. The goal is to prove your impact without ever putting the people you serve at risk.
Capture once, at the right moment, and use it everywhere. That is the whole discipline. The reward is that reports and proposals stop being a scramble, because the work is already done.