Choose representative journeys
Pick a few important entry points and follow them through to an outcome. Include a content page, a navigation path and a form if one exists. Record the device, browser and exact step where a problem appears.
Separate observations from causes
A slow-looking page is an observation. An oversized image may be a cause, but check it before prescribing a fix. Save enough evidence that another person can reproduce the problem.
Prioritize and verify
Rank issues by their effect on users and the work needed to address them. Give each change an owner and a concrete acceptance check. Revisit the original journey after the fix instead of assuming a closed task means a solved problem.