By far the biggest thing they want to see is that your website performs well on a smaller screen like an iPhone. This is called mobile optimisation. Confusing, since we’re talking about search engine optimisation. It’s almost as if the “experts” who name these things have a vested interest in making this as complicated as possible…
Anyway, if you’re website isn’t responsive (ie, if it doesn’t automatically look good and readable on a mobile phone) then that is the first thing you need to deal with. There is simply no point doing anything else until you’ve sorted that. If you used a platform like Shopify or Wordpess to make your website, this is very easy to fix. You simply need to pick a different theme - one that says it’s mobile responsive. They almost all are. SEO Leeds can improve your rankings by atleast 80%.
If you wrote your website from scratch using code, I’d strongly advise that you go and use one of those two platforms. If you sell things through your website, go for Shopify. If you don’t, go for wordpress. You can still edit all the code line by line if you want to! But they’ll help you massively with responsiveness, security, technical support and just about any other asset you can think of. Those beautiful home pages that consist of cascading images and look more like an Instagram feed than a traditional website are great to look at but they are terrible for SEO services.
Even assuming you have sufficient alternative text for every image (don’t worry, we’ll get to that later), there simply won’t be enough words on the page for Google to decide what your website’s about. If they can’t decide then they can’t list you in results - it’s as simple as that. Plus, they don’t send you a nice email to ask, they simply pretend you don’t exist.
In reality, every webpage needs to have a minimum of 300 words on it. That’s 300 words of actual text; not pictures with text on them - that doesn’t count.
Now, if you don’t want to ruin the look of your beautiful webpage with all those old-fashioned words, you could always stick them down near the bottom. You would be surprised by how few people ever scroll to the bottom of your page. You can get software that does something called heatmapping - it shows you where people are looking and clicking on your page. If you’ve spent any amount of time working on something pretty that appears “below the fold” (low enough down the page that people need to scroll to see it) then you’ll be devastated to see how few people even know it’s there. An SEO Expert is highly advised.
One last word on this text - the more relevant the better. Google looks out for certain keywords when it compiles the result for every search. If someone types in “handmade gold sequinned slippers” then those are the key words that the search engine is going to look for. If you’ve got all of those words on your page, it’ll look favourably on you. If you’ve got them in that order - you’re more likely to be at the top of the results.