Most people and companies would benefit from their websites gaining more traffic. Developing a website to be search engine friendly is a crucial element of "On-Page SEO" and comprises of:
A major factor of search engine friendly development is having a mobile friendly design. Google began penalising and lowering rankings for websites that didn't conform to their "mobile friendly" standards. This applied to both desktop and mobile searches. To avoid a negative impact on search engine rankings websites had to make sure they had a mobile version of their website that passed Google's "Mobile Friendly Test".
Your website should also be structured correctly, an obvious start being delivery of information in the order the visitor would like to see it, such as a relevant title at the top of the page explaining what they can expect to see on the rest of the page. A title would be useless if it was placed at the bottom of the page after the visitor has already seen everything they needed to. It would also be useless if it was irrelevant to the page it was on. A simple example is a contact page shouldn't have a title that says "The Best Cleaning Service Around" but something like "Contact us for your Cleaning Needs".
A well structured website without coding errors, with relevant content in the right order, that follows recommended practices will be considered as a better option to deliver as a search engine result than a competitor's website with errors, "spammy" content that doesn't follow the latest recommended practices.
By taking a search engine friendly approach to the development of your website you are aiming to make your website visible to search engines thus making it more easily accessible by people who use search engines. A search engines aim to is quickly deliver relevant information based on your search and in order to gain organic traffic from web searches, your website needs to be seen as "relevant info". Ensuring the information and content on a web page is relevant to what you say is on the page is will help your website be considered "Mobile Friendly".
Other factors that are worth discussing but really would require their own designated pages are page speed, micro tagging and appropriate "meta" tags.
With the amount of people accessing the internet and websites via mobile devices, often by using mobile data, it is important that websites are designed to load quickly to avoid visitors looking for an alternative website to find what they're looking for. A website that isn't optimised for speed will be penalised in search rankings as the search engine may decide that a different website which loads quicker should be displayed higher up a results page than a website that loads more slowly.
Micro tagging benefits your website by guiding search engines to information they may already be looking for. So for the price of a product, it is recommended to micro tag this as the "product price" so the search engines can display on their results pages, alongside the result for your web page, the price of the product. For a product this can be extended to the product name, product code, stock levels and current ratings. By micro tagging key information, search engines can quickly deliver more information to potential visitors and keep information up to date more easily.
Meta tags aren't displayed on the page itself but are available in the pages code. They are important to help search engines distinguish what information is on your page and affect the text that is displayed as a search result for that particular page (see image below).
A search snippet example for a website appearing in Google
There are both meta tags that search engines are expecting to see within your pages code in addition to tags that aren't expected but can make your page more appealing to search engines than a competitors.
I can ensure your websites design meets Google's mobile friendly standards, has all the boxes ticked that search engines like to see, doesn't fall foul of "black hat" techniques and appears for relevant search results, ensuring your website has maximum visibility online.