What causes weak staining on tissue sections, and how can it be avoided?

1. Antibody concentration too low or incubation time insufficient. 2. Incomplete antigen retrieval. 3. Over-fixation of tissue. 4. Insufficient detection system sensitivity. 5. Inconsistent section thickness. Solutions: optimize working concentration and extend incubation; ensure fresh retrieval buffer and proper temperature; control fixation time; use a high-sensitivity detection system; keep section thickness uniform.