Pay your suppliers.
A couple of weeks ago, I wrote a blog titled "Just pay me", which stirred up quite a bit of discussion. This isn't really the time to answer all the comments I received (I answered the major themes in the comments on that post), so I'll move on. The reason why I mentioned that post, though, is because it's one side of the coin when you're running a business, and this is the other.
Pay your suppliers.
It's as simple as that. If you hire someone to do work for you, whether it be designs, accounting, or a plumber, then pay them. Once again, this shouldn't come as a shock to most people - if you get a service, general convention says that you should pay for it. The bit which doesn't seem like common knowledge, though, is when to pay.
Pay your suppliers now.
Don't put it off. The money has already been spent, no matter how long you put off actually spending the money. The day you receive the invoice should be the day you pay the invoice. If you absolutely can't manage to pay it immediately (it can happen - sometimes you're waiting for your clients to pay you) then you should pay it as soon as possible, and contact your supplier to let them know that you've seen it, and will pay it. If you don't think you can pay it by the due date, tell them. Maybe they will accept a part-payment now, and the rest later.
If you're good to your suppliers, they will be good to you in return. You will be one of those people who might get special rates simply because you're good to work for. Suppliers (who do often talk amongst themselves) will be more likely to take on work for you, or to recommend that people take jobs you offer. If you also do work for your suppliers, then they'll be more likely to pay you promptly.
No one will ever complain about being paid promptly. In an ecosystem where waiting until the due date is the norm, people will remember being paid the day that they send the invoice. You will get better work out of suppliers who want to work for you, and your suppliers will be happier.
Pay your suppliers, and make the world a better place.