Asking customers for testimonials? Try including a prompt with your request. Something to avoid you ending up with generic “This company is great!” comments.
Basecamp is the case study of case studies for this:
What was life like before they chose you? (hint: rubbish)
How have things improved since becoming your customer? (hint: great, boosted sales, higher productivity, happier smiles in the office)
What was it about your service you liked the most? (hint: focus on a USP or something that separates you from your competitors)