"Canned response" is a popular feature present in some email apps and most helpdesk systems, that allows inserting a quick pre-defined text into your response to a customer. Just like "self-support" help sites and searchable knowledge-bases can help you get rid of up to 45% of incoming support requests, the "canned responses" can speed up the remaining 55% drastically. If you're not using this feature you're really missing out.
I've analyzed tickets from our own support desk
This one is obvious. Prepare answers to the frequently asked technical questions - "how do I install this", "what are the system requirements", "how do I make it do XXX" etc. As well as not-so-technical ones: "do you have any big customers in your portfolio", "what is the upgrade policy" etc
Make sure you have a nice set of calming replies in your canned responses, along with a bunch of apologies. Also, try to avoid "robotic" phrases like the "Please accept our apologies for the inconvenience caused" nonsense, you're not Comcast after all. An honest "I'm sorry, this is totally our fault" is much better. "Here's what we're doing to avoid this in the future" is a nice addition as well. Make sure you check our How to apologize to a customer blog post for further info.
Be personal: many helpdesk systems (including our support ticket system) allow inserting "variables" into the canned response templates. Like "You're welcome %FirstName%" or "Dear Mr %LastName% please find the quote attached". This helps you add a nice personal touch
People ask for discounts all the time. So have a bunch of "promo codes" prepared if your company policy allows this (which I believe it should - a discounted sale is still better than no sale at all).
"Reseller quotes", "non-profit pricing", "educational deals" and "I want this for free" are another frequent types of support requests. Have those ready. For example, if your company offers some kind of a free-deal - like, "free 6-months license for a blog review" - describe this in a canned response too.