My partner Albert has a great short post up on Radio Silence.
I have found that an important ingredient is to set realistic expectations about how long it will take you to respond to a new draft or a set of questions. Don’t say “we will get back to you tomorrow” if you already know that your lawyer is traveling and it will take you three days to get back.... Often the net result of that are several days of “radio silence.” During this time the other side will start to ponder and more likely than not draw all the worst possible conclusions (“they are stalling”, “they are shopping the deal”, “they want to recut the deal”).
I've often said that a venture investment is like a marriage and the negotiation is like the engagement. So this is important stuff to get right.