(1) Post testimonials at every pre-sale customer touch point. Try and put different and relevant picture testimonials on each page with testimonials from people whom the audience instantly recognizes (i.e. influencers in the niche). For e.g. if you are selling SEO software, get a testimonial and picture of Rand Fishkin. I rarely read testimonials unless the picture is of someone I’ve heard of (or belongs to a company I respect).
examples of testimonials on various pages -
(a) Homepage - testimonials on what and how customers got value.
(b) Pricing Page - testimonial on how the product is worth every dollar (how it made me $X or saved me $X).
© Help/Support page - testimonial on how customer support was helpful
(1 & 2) Always ask them if you can put their testimonial/logo on your website. The best time to do this is after you’ve had a good interaction with them - e.g. answered some customer support issue or after they made their first dollar using your product.
(3) “As seen on” builds instant trust in your product. Logos are awesome for this the same way as profile pictures are awesome for testimonials. Best if the logos are in plain grey, so as to not distract the reader.
(4) Makes sense only if you have a large enough number to be impressive. This works on “herd mentality” - if 10,000 users love your product, I think I might love it too. A better number to publish would be some metrics to measure value. e.g. “sent 18,432 invoices last month” [see No 6 below]
(5) Verified/Secure badges would probably work for a non technical crowd. It’s a distraction for technical folks.
(6) Only, if your users care about how many sales you made (and how it benefits them). For e.g. If you are selling on behalf of your customers. For.e.g Gumroad could put something like “Our customers made $8,000,000 in sales this month”.
(7) Helpful if I care about whether other people from specific area/industry are ordering the product. For e.g. If it’s a software product aimed at developers, a “24 mins ago a new sale from a developer at Google Inc” might work wonders.
(8) As a customer I expect not having to contact support at all. So I can’t think of any reason why average response time of 2 minutes would matter to make a purchase decision. You could instead put something relevant about the service you provide. For e.g. DigitalOcean “Deploy an SSD cloud server in 55 seconds.”