Disavowing links is meant for clear cases of manipulative or spammy links you can't get removed directly, not a fix for a normal, mixed backlink profile.
Confirm There's an Actual Problem First
Most sites have some low-quality links naturally, and disavowing broadly without evidence of harm can do more damage than good.
Try Removal Before Disavowal
Reaching out to request a link's removal is the preferred first step; disavowing should be reserved for links you can't get taken down.
Document Your Reasoning
Keep a record of why each disavowed domain was flagged, in case you need to review or adjust the file later.
Next step: Use the Disavow File Generator to format your list correctly if you've confirmed a genuine problem.