Keep the gig conversation open. Don’t deliver a gig with a “Please make a review of my product.” As some buyers don’t care if you delivered on time or think you can read their minds, and sometimes they except something completely different or change their minds too quickly. If you keep the line open some buyers will ask for a little change or fix on the delivered product, it all depends on what you are delivering, and how much it is worth. You may as well take advantage from their response to explain why you shouldn’t change or modify your delivery, or ask for extra gigs.
If you want to avoid bad reviews, deliver on time and be quick on your response. For example. “Hi, the video is ready!” or if you are close to the deadline “Hi, Thanks for your patience your video is ready.” That will be enough for the costumer to decide if he/she is satisfied with your service.
Don’t be over eager to get feedback, and don’t promote changes in the delivery. Saying “Please let me know if you are satisfied with my video” will only lend your buyer to hesitate and end up asking for changes in the end. You may ask for extra gigs, but it might get tricky in the long run.
Be quick and go to the point, and make your client know that you are also a human being with limited time and resources. Oh and never sound too formal-robotic. Keep it natural.