When preparing to sell your house, conducting a thorough home inspection can help identify any issues that need to be addressed before listing the property. Here's a checklist of 20 essential points to consider during a house inspection for potential sellers:

Exterior Walls: Inspect for cracks, water damage, or signs of deterioration.

Roof: Check for missing or damaged shingles, leaks, mold or any signs of aging or deterioration.

Gutters and Downspouts: Ensure they are clear of debris and functioning properly and 6 ft away from foundation. 

Foundation: Look for any cracks or shifting as well as low spots with pooled water that could indicate structural issues or future leaks into basement.

Windows and Doors: Check for proper operation, weatherstripping, and any signs of damage.

Siding and Trim: Inspect for rot, damage,  need of replacement or just repainting.

Landscaping: Trim trees and shrubs away from the house and ensure proper grading for drainage.

Driveway and Walkways: Look for cracks, potholes, low spots or other damage that may need repair.

HVAC System: Have the heating, ventilation, and air conditioning system serviced and ensure filters are clean or replaced. 

Plumbing: Check for leaks, watermarks, dripping faucets, and ensure toilets and sinks are functioning properly.

Electrical: Inspect outlets, switches, and the breaker panel for any issues or safety concerns.

Insulation: Verify that the insulation is adequate and properly installed in the attic and walls.

Attic: Check for signs of leaks, proper ventilation, mold and insulation coverage.

Basement or Crawl Space: Look for any signs of water damage, mold, or structural issues. Here a moisture metre will give a good indication of water penetration. 

Chimney and Fireplace: Inspect for any damage or blockages and ensure proper ventilation.

Appliances: Test the functionality of major appliances, such as the refrigerator, oven, dishwasher, and washer/dryer.

Lighting: Verify that all light fixtures are working and replace any burnt-out bulbs.

Smoke Detectors and Carbon Monoxide Alarms: Test and replace batteries if needed. (you should have one on every floor as well as one in each bedroom) 

Safety Features: Ensure handrails, stair treads, and other safety features are secure and in good condition.

General Cleanliness: Thoroughly clean the house, including carpets, windows, and all living areas.

Keep in mind that this checklist provides a general overview, and it may be beneficial to hire a professional home inspector for a more comprehensive assessment. Additionally, local regulations and climate conditions may require additional inspection points specific to your area.