Closing a deal with an enterprise or a corporate customer is a major boost for any business, small and big alike.

Getting paid, however, is another thing entirely.

It can go as smoothly as you’d hope, or end up in a total mess. It all depends on the way you invoice your customers. Once received and recorded, the invoice triggers a series of processes that result in money hitting your account—unless something goes wrong.

The key to having your invoices cleared on time lies in the details. The following tips come from my two years in accounts payable and accounts receivable, and following them will save you time, money, and a good deal of stress.

1. Know where your invoices actually go

While dealing with big companies, you have to bear in mind that Accounts Payable is one of the first processes to be outsourced and automatized. And where there’s automatization, the tolerance for error is next to none. That applies to your invoices too.

This means someone in a different country (and even a different timezone) probably books your invoices. Whether it’s a third party or a shared service center, the quality standards are rigorous. They will not hesitate to reject an invoice, especially from a small vendor, on a slightest suspicion that something is off. What might seem to you as a trivial detail could actually cause serious repercussions for the outsourcing partner in case of an audit.

Furthermore, AP operates with a high volume of documents and each of them is assessed very quickly. There’s no time to analyze every invoice in detail—it’s either correct or not, and that’s it. Make sure your invoices are accepted and approved right away. How? Well, by complying!

2. Nail it from the start

The majority of payment issues I’ve seen could have been easily avoided by simply following the client’s billing requirements. The more people involved in setting the deal, however, the bigger the chance that this information gets lost.

Sales representatives are often the ones that receive the billing instructions, but as they focus more on securing new leads, they tend to neglect the formalities that come after.

Make sure your sales and billing are on the same page. Don’t wait until the invoice is past due to verify if it’s been issued correctly.

3. Keep your invoices readable

Whether you send electronic or paper invoices, they are most likely scanned at the very beginning and routed to an invoice-reading software. The AP accountant verifies them next.

This is where a lot of things can go wrong. First of all, these applications are not good at reading color. You might be tempted to spice your invoices up with different hues, but it’s best to keep them simple. Having all of the text and numbers in black is a must.

Additionally, don’t scan the invoices yourself—the resulting image in the customer’s system is sure to be unreadable. The right way to go is to generate a PDF.

Second, make sure that the essential details (invoice date, due date, number, PO number, company name and address, amounts, and tax rates) stand out. They must be easy to spot at a first glance. Otherwise, the invoice could be rejected right away, even if the information is actually there.

4. Bill the right entity

The bigger the company, the more entities it’s likely to have. Unless the order form says otherwise, invoice the unit you’re actually doing business with.

Many vendors tend to address their invoices to corporate headquarters when in doubt about the correct billing address. AP is sure to reject them and ask to resend the document with corrected details.

Additionally, don’t ever shorten the company name or its address. Some countries (Singapore, for example) have very strict regulations regarding this, and AP might not accept invoices with abbreviations or missing details.

This might sound absurd, but sometimes I had to reject invoices that had a wrong floor or street number in the client’s address. Use exactly what you’ve been provided with by your business partner.

5. Respect the purchase order

Your customers will most likely require a purchase order (or “PO”) number on your invoice. Make sure to verify if that is the case and comply with all the information included in the PO.

The PO is what AP looks for first as they book invoices using this number. If it’s not there or it’s hard to spot, the invoice could be rejected and miss its intended payment run. Keep track of the financial period the PO covers and the available cash. Sending an invoice with a PO out of date or out of funds is sure to delay the payment by days, if not weeks. This is especially problematic during the transition from one fiscal year/quarter to another.

It’s also a good practice to keep one PO per one invoice. It might seem more convenient to include several POs in one document, but it’ll make it harder for AP to book, especially when there’s an issue with one of them.

6. Bill in the right currency

Currency discrepancy is another common reason for delayed payments, especially when trading with foreign entities. Be extra careful when you deal with such.

Some countries, like India, make it extremely difficult to process wire transfers in foreign currencies. I’ve seen payments dragging for months because of this, resolved only by issuing a new order.

In case you’re invoicing your customer in a currency different than local, you might also need to provide their domestic equivalent of all the amounts on the invoice, including and excluding taxes.

7. Revise your address book regularly

Keeping your contacts up to date is of crucial importance, especially when you don’t invoice your customers frequently. Big companies always improve their processes and data management systems, which often results in changing email addresses.

Usually, they communicate it in advance, but automated emails could easily get lost in your inbox or filtered as spam. If you send invoices to a personal email, make sure to include a generic finance or accounting address in CC. People come and go, so don’t make the mistake of reaching out to someone no longer with the company.

AP accountants might also not check their inboxes as often as they’d like to. Submitting your invoices through generic channels will ensure they’re dealt with within the standard time frame.

8. Follow up with a smile

Whenever you follow up with AP about your rejected invoice or a delayed payment, being friendly will go a long way. Naturally, you have the right to demand the money on time, but taking a negative tone with an AP clerk won’t help.

The issue is probably not their fault. They’re much more likely to go an extra mile for you if you show empathy and kindness. Their job is extremely mundane, so treating them as people rather than machines will work in your favor.

AvatarMichał Kamiński

Michał Kamiński is a former corporate mouse, currently teaching English, urban gardening, and writing about startups and new technologies for Starting Things Up.