You should* also be working with a banker who sells companies for a living. They will take some % (10%? Who knows) of the deal, but in my limited experience it seems worth it, since they will also help you make introductions and give advice - maybe not perfect advice but it will be advice that will either raise the price of your sale, make it happen faster, or promote some corrupt agenda the banker has (i.e. work with a banker who comes to you from someone who can vouch for them)

There are obviously some things to be very careful in terms of shopping for a deal, but that's also how higher valuations occur. And, if the acquiring company doesn't want to deal with it they can give you a "no-shop" offer that is higher, in addition to the breakup/no-deal fee.

*This "should" in addition to everything else above is just an opinion. I've only been in a company once that was acquired successfully and heard stories about other situations, so take it for what it's worth which might be nothing :-)