SEO best practice guide for URLs

Today we’re going to take a look at the basic building block of not just SEO, but your very web presence itself: the humble URL.
Does the structure of a URL (or uniform resource locator for pointless trivia fans) matter to SEO? Yes it does, in fact there are many best practices you should consider when creating a URL for your content.
1) Keep a simple, readable structure
This is Google’s number one most important advice – “a site’s URL structure should be as simple as possible.”
It should be logical and readable for human beings. So you’re URL should be www.example.com/SEO-advice-for-beginners not www.example.com/index.php?id_sezione=360&sid=4j3898enno0223bns983201djis03
Use actual words and sentences that anyone can understand, especially when copied into other documents or emails. Stay away from eternally long random patterns of letters and numbers. Nobody wants to click on that.
Gov.UK recommends it should be as short, memorable and unambiguous as possible, especially if a URL is going to be referred to offline.
2) Use hyphens to break up words in a URL
Punctuation is key in promoting readability in URLs. Google recommends hyphens (www.example.com/SEO-advice-for-beginners) instead of underscores (_).
3) All URLs must be in lower case
If your URL contains upper case letters, redirect to the lower case version. In some cases (if you’re hosting with Linux/Unix servers) identical URLs where the sole difference is a capital letter – example.com/webpage versus example.com/webPage – can be considered different pages.
4) Stop-words in URLs
It used to be that you were recommended to avoid stop words (a, an, the) in URLs, but that doesn’t matter anymore. A URL just needs to make sense to human eyes.
5) Your headline doesn’t have to match the URL exactly
In fact it’s a good idea to vary the text, and make it more concise. If your headline says ’25 super-useful SEO best practice tips for beginners’ it may be useful to pair it with a simpler URL: 25-SEO-best-practice-tips-for-beginners
6) Make sure your keywords are near the front of a URL
It’s still good SEO practice to ensure a page’s keywords are near the front of a URL – but it still needs to be readable AND not stuffed with keywords.
7) Use a single domain or subdomain
According to Moz, “a company blog is far more likely to perform well in the rankings and to help the rest of your site’s content perform well if it’s all together on one sub and root domain.”
There’s apparently plenty of evidence to suggest that when a company moves content from a subdomain to a subfolder, they see a positive boost in search visibility in traffic.
8) The fewer folders (slashes) the better
Again, according to Moz, the more slashes your URL has, won’t necessarily harm your performance, but it can create an illusion of depth and make indexing your content more complex.
9) URLS should be the verb stem
As recommended by Gov.uk – you should use the term ‘apply’ rather than ‘applying’ for instance.
10) Avoid high numbers of URLs that point to identical or similar content
Overly complex URLs with multiple parameters (such as in point number one) can cause problems for Googlebots, by creating too many different URLs containing similar content.
Google provides a huge list of how this problem can be created in its guide as mentioned in my introduction. It includes:

Additive filtering of a set of items. If you provide different views of the same set of items or search results, especially if you let users filter by a certain criteria in an additive manner (for example: hotels in New York and with a panoramic view), the number of URLs on your site will “explode.”
Dynamic generation of documents
Problematic parameters in the URL (such as session IDs)
Sorting parameters
Irrelevant parameters in the URL, such as referral parameters
Dynamically generated calendar

How to fix URL problems
Here are Google’s recommendations for fixing problematic URLs:

Use a robots.txt file to block Googlebot’s access to certain URLs. Such as dynamic URLs or URLs that generate search results.
Avoid the use of session IDs in URLs. Use cookies instead.
Shorten URLs by trimming unnecessary parameters.
If your site has an infinite calendar, add a nofollow attribute to links to dynamically created future calendar pages.
Check your site for broken relative links.

The above tips were collected from various resources, including Google’s own advice, Moz’s guide and the Gov.uk style guide.
Please let me know of there’s anything missing, and I’ll add in a future update.
Source: ClickZ
Link: SEO best practice guide for URLs