I see it all the time. One of my portfolio companies raises a decent round and a subtle change comes over the company.
'We have money for 6/9/12/whatever months! Time to go kick ass in the marketplace!'....or not...
First off, the money is probably not going to last as long as you think it is. Rather than a spending spree, keep the tight budget controls and the burn rate low until you really need those additional resources. Hiring too far in advance of market needs, or moving to an expensive office, just ramps up burn and may not really yield more market success.
Second, sit down with the team and carefully understand collectively what the best uses of funds are going forward. Even last month's plan may be out of date, given a fast changing markets or competitors. Sticking to some 'investment plan' because that what you sold to the investors can be a big mistake at times. Be sure you spend time with the investors explaining carefully why there has been a change in priorities.
Finally, keep on raising capital. Just because you have a war chest does not mean it lasts forever. The big sin here is complacency--waiting until you have only 3-4 months of cash in the bank and then starting out to get another round is....stupid. I'll explore the wrong and right investor meetings to do this in another post.