We're now seeing the same sort of problems in the QR space. Marketeers are using them without any really thought of how or if they work.

It doesn't need to be this way. There are some simple rules to ensure you create a great QR code experience.

The Ten Commandments

It's always pleasing to have a list of ten things to do. In reality, successful use of QR codes can be boiled down to 8 simple commandments.

1. Your QR code shall be large enough and clear enough to scan easily.
2. Your QR code shall contain the minimum amount of data necessary.
3. Your QR code shall resolve to a mobile friendly resource.
4. Your QR code shall work for an international audience.
5. Your QR code shall work on all platforms.
6. Your QR code shall generate statistics and thou shalt analyse them.
7. Your QR code shall have a sufficient call to action.
8. Your QR code shall be tested.

What do those commandments mean? Read on...

1. Scanning

This is really basic and boils down to 4 key points.

• Black ink on a white background. Yes, you can use dark colours on light backgrounds - but if you want it scanned by the majority of people, keep it simple.
• Whitespace around the edge. This should be the equivalent of 2 rows.
• Print it large enough so that all bits can be seen
• Keep it square

Here's a code which violates the majority of the above.
London South Bank University has a code with minimal whitespace, so small the newsprint smudges, and deformed so it isn't perfectly square. As a result, the code isn't particularly scannable.

2. Minimum Data

The fewer bits of data in a QR code, the smaller it is. Obvious, no? The small the code is, the larger and clearer we can print it - making it easier to scan. The less data in the code, the quicker it is to scan. This is especially important on phones with low camera resolution.

There are two ways to go about reducing the amount of data you pack into a code.

Reduce Size

Both these QR codes lead to the same web page - this post - but one has a shorter URL than the other.

Appropriate Error Correction

QR supports 4 levels of error-correction. This means if the code gets damaged or disfigured, it should still be scannable.

If you're printing on signs which are going to be exposed to the elements, it makes sense to increase the level of error correction. Most users can get away with a very low level. Here are the differences

3. Mobile Friendly

QR Codes are mostly scanned by mobile phones. Why then, would you make a code point towards your mult-megabyte, flash heavy, non-mobile main site?

Mobile Web

This code from Superdrug takes you to an abomination of a site.

Not only is the site hard to use on mobile, it will take the user ages to download - especially if they're not in 3G or WiFi coverage. If they're paying per MB, they won't thank you for taking them to such a useless site.

Mobile Phone

UK users: Under no circumstances use "free" numbers like 0800, nor "premium rate" numbers like 0845 & 0870. The call costs to these numbers from most mobile phones is extortionate. If possible, use a geographic number, mobile number, or an 03 number.

4.International

In the above example, you will have seen that my mobile number was rendered as starting with +44. That's because you don't know if the mobile phone scanning the code has a UK SIM in it. Nor do you know if the user is roaming. If you are doing anything with calls, make sure that international users can access your code.

5. Multi-Platform

The world is more than an iPhone. If the page or service you are linking to only works on one phone - you've failed.

That said, if you genuinely only have an iPhone game, make sure that you point to a site which will detect the make and model of the phone and direct it correctly.

For example, rather than pointing a QR directly to iTunes, point to an intermediary site. If a non-iPhone scans the code, you can redirect it to your mobile friendly site - or a page telling them that it's not available.

This is also useful for the next commandment.

6. Statistics

You should be tracking hits to your website anyway - but these are the minimum you must consider when implementing a QR code.

What

Do not point your QR code to your main site - always track the code so you can see if hits are coming from QR codes. EG

example.com/qr
qr.example.com
example.com/foo?s=qr

Who

As mentioned above, track the User-Agents hitting your site. Are you getting more QR hits from Android or BlackBerry?

Where

QR codes are cheap. You can create a different QR code for every campaign you run.

example.com/foo?s=6pack
example.com/foo?s=2litre
example.com/foo?s=6litre
example.com/foo?s=GuardianNewspaper
example.com/foo?s=NYT
example.com/foo?s=90210

7. CTA

What does your QR code do? Where does it lead? What benefit will the user get from scanning it in? Does the user even know what to do with a QR code? What should they do if they don't have a QR scanner?

Consider something like these examples.

Get the latest news on your mobile - scan the code to visit bbc.mobi/news

Download our app for the best deals. Grab a free scanner by searching for "QR Code" in your phone's app store.

Donate to our charity. Scan the QR code with your smartphone to give just £5

Call us to find out more. Scan to call 03069 990123

For more great ideas, read How to create a great call to action.

8. Testing

Buy a dozen cheap handsets from a pawn shop. Test your code. Test the code in a variety of lighting conditions, at a varying range of distances, at different resolutions, on different networks, using a wide selection of QR scanning software.

Your users are not a homogeneous bunch. The people seeing your QR code don't all have the same make and model Android phone as you do.

You wouldn't test your website only in Internet Explorer, would you? You'd make sure it worked in Firefox, Safari, and Opera. Let it be so with your QR codes.

Putting It All Together

You're not too stupid to understand how to make effective use of QR codes. The "commandments" are mostly just common sense.

Use QR codes wherever they seem appropriate - but make sure that they're scannable, work for everyone who scans them, and lead somewhere useful.

Suggestions for commandments 9 & 10 are welcome. Please drop them in the comment box.