There are many aspects to working in construction, and different people will have different strengths. You might be well trained in tiling, drywall, and painting, while others might be better at framing, roofing, and installing insulation. You can describe your strong points as related to hard skills, as mentioned, but you should also include your soft skills. You could add that you work well on a team, have excellent communication skills, and have a strong work ethic. The interviewer wants to determine that your strong points will benefit the company if they hire you.