Form rejections are tough, but the way in which you're getting rejected over a long enough period of time can tell you something about where the problem is. If you're getting a lot of form rejections, and you're not getting any requests for partials or full manuscripts, that can mean that a) either your query is not getting the responses you want, and people aren't interested in reading more, or b) if you have been including some opening pages whenever permissible by an agent, those opening pages also aren't gripping the agents enough to ask for more. I've had this happen to me.
If you're getting regularly requested, then that's great, your query is doing its job, but then getting form rejections on partials and fulls--which does happen--then the problem is with the manuscript itself, not the query you're using to intrigue the agent. I've also had this happen to me.
Realistically, you're going to get more form rejections than anything else, unless you're one of those statistical flukes who's writing is so genius you immediately get offers on your first 10 queries and then have those 10 agents offering their first born to you in order to represent you. You have to remember that there are many, many different factors at play that can lead to an agent deciding to respond with a form. If you're really concerned that your query is not getting the attention you want, run it through Query Letter Hell, here in the forums once you've got enough posts, and thicken your skin; the people there will definitely help, but depending on your sensitivity and disposition, you may not get away from the experience unscathed. Your query and your opening pages are basically your teaser to the agent. You have to try to make those as appealing as possible and then hope that the rest of your book lives up to the promise you've laid out in your query and first 5-10 pages. Just make sure that if you're putting this much effort into creating an intriguing tease, the rest of your book lives up that promise.
A lot of people here advocate putting out queries in batches to see if you're getting any "nibbles" and then, if not, reworking your query to see if it gets a better response. That's really good advice, and if it resonates with you, follow it. Just keep in mind that this can be for the long haul. I did eventually get offered representation from an agent, but it took a few years, and over 400 rejections on queries with different books to do it.