Q: I have recently sent out query letters to a lot of agents and got some helpful advice, though the book I wrote wasn't for them. Now I am writing a new book and following the advice these agents had given me. My question is: Since I queried these agents already with one book, is it OK to query them with this new book? I'm sure I know the answer to this question already, but I didn't want to query them again after this new book is finished and they think I am being pushy. The thought "oh no not this guy again" comes to mind.
A: Resubmitting is a strange thing. I get a lot of questions about resubmitting the same work to an agent after it's reworked, but this question is unique in asking about a different project.
You should be A-OK in submitting your second project. Just evaluate your submissions. If several agents turned down Project 1 because it didn't suit their needs or wasn't where it needed to be writing-wise, etc., is Project 2 different enough and good enough not to suffer the same fate?
Now, on to the more common question: Can you resubmit the same work to an agent? Usually, you wouldn't want to, naturally, because the agent has already passed on it. But the exception is those rare circumstances where the agent has passed on some concrete reasons as to why the work was denied. Perhaps the agent's comments match the comments from your critique group. You take the criticism to heart and retool the ms. At that point, you could submit - and make sure to mention to the agent that you have completely rewritten the work, taking into account her previous advice.
Crazily enough, The Buried Editor blog just blogged today about this exact same subject, and gave a very upfront response about resubmissions (that basically disagrees with this post). (Read the whole thing here.) To summarize, the post said that when she rejects a manuscript, she won't consider it again, even if all the personal advice she offered with the rejection, if any, is taken into account when the writer completely retools the work.
So the moral is: It depends on the agent. Some may consider resubmissions. Others won't.