Cash flow tips are a list of tips I'll  be presenting on ways to improve the cash flow in your business.  They  will cover a wide range of topics.  They are not pie in the sky ideas,  but tried and true methods I've used with clients or the companies I've  managed.  I decided to pick a somewhat simple one today in talking about  your accounts payable.
One  way to improve your cash flow, especially in the short run, is to  stretch out your accounts payable, in other words, taking longer to pay  them.  For example, let's say you purchased $100,000 of widgets from  XYZ, Inc. with Net 30 day terms.  XYZ expects payment from you in 30  days obviously, but if you take 45 days to pay, you've now used XYZ's  money for an additional 15 days with (theoretically) no cost of money.   When I discuss this with clients, I get two responses, either 1) you  can't do that, it's unethical, or 2) of course you would, industry  average is 45 days to pay anyhow.  Both answers are wrong.
First,  the unethical argument.  I would not recommend stretching out a payment  like this without talking to the vendor first.  Especially in our  example of a large invoice taking an extra 15 days over terms.  Over the  years, I've found most (not all, but most) vendors very willing to  allow you extra time to pay an invoice whether you are in a cash flow  crunch or your business is seasonal, IF (that's a big IF) you call them  up front and talk about it.  For some reason, most people are averse to  this, but I highly recommend it.  Calling up front helps you establish a  relationship with the vendor and lays a groundwork should you attempt  to renegotiate terms to 45 or 60 days.   
Try  calling to renegotiate terms with a vendor or ask for a favor if you've  been paying 15 days late on all your invoices and there is no  relationship and you are typically in for a big surprise.  Which  addresses the second response of 45 days being industry average.  Yes,  in most cases that's true and in some cases vendors don't care that you  pay late, don't know you pay late or will ignore your late payments  until it is time to renegotiate terms or pricing.  With no relationship  with your vendor and late payment history, you stand in a difficult  position to renegotiate.
I've  worked with numerous vendors to modify terms either temporarily or  permanently.  Most recently working with a manufacturer with very slow  sales in the 1st quarter due to seasonality.  When you have  regular conversation with vendors, they often anticipate the call and  again, most are willing to work with you.  Assuming you have an average  payables balance of $500,000 and let's assume you are able to get all of  your vendors to agree to temporary 45 day terms, that's $250,000 in  cash or that you don't have to draw on your line of credit.
I'll  repeat again how important that communication is, especially in this  economy when many companies are stretching out their vendors to stay  alive as a last ditch effort.  That's not what I am talking about here  and is a much different, urgent issue.  You need to communicate to your  vendor what you need and why so they don't assume you are in last ditch  effort mode!