On-page SEO is done on your website to make it eligible for Google to understand what your website is and also improves the performance once we implement this on-page factors.
Meta Title : This describes your website using primary keywords which should be 55–60 characters having more than 65 characters will hide your title in Google Search.
Meta Description: This defines the meaning for a website and it’s pages every page on your website should have unique meta descriptions which helps your sitelinks to automatically show in SERPs. (155 characters limit)
Meta Keywords: This are not required but their is no harm in keeping them, every page should have 10 keyword phrases for each url no same keywords should not be repeated in other pages.
Image Alt Tags: Every website has images should for google to understand that image we need to give an alternative text to that image so that google can understand what exactly is the image about.
Header Tags: This are very important because their make the first impression when a user visit your website, each page should have only one H1 tag and should contain your primary keywords in it.
Content: Optimize your content with your primary keywords for a particular page for example the page is about SEO then include only seo related keywords and links don’t include keywords which are not related to SEO, your content should be long enough and unique without duplication.
Keyword Stuffing: Having more keywords on a page is a black-hat practice which can penalize your website, so maintain the ratio of atleast 2–5% keywords per page not more than that and don’t repeat the same keyword again and again instead use the keyword phrases.
Sitemap: Sitemap is used to crawl your website pages so that google can send a spider to check your website content and urls so that your website can get crawled in Google, we have different sitemaps such as sitemap.xml, sitemap.html, ror.xml, news sitemap, videos sitemap, image sitemap, urllist.txt etc
Robots.txt: This is very crucial for any website to get indexed in Google having a robots.txt file helps your website pages get indexed.
Internal Linking: Interlinking is very important to easily navigate between pages so that their is distraction for the user to get confused this should also be used in blogs and website content with related links.
Anchor text: Your anchor text and url should match each other which is a good practice for ranking easily.
Url Structure: Your website should maintain one url structure and should be seo-friendly to get ranked easily and each of your url should have your targeted keywords, it means your title should match your urls.
Mobile-friendly: Making your website mobile-friendly is most important because now a days most of the users rely on mobiles, tablets stats say 80% of users open their websites or do their shopping via mobile rather than desktop, so it’s better you make your website responsive for mobile version.
Outbound links: Use links in your website content which are related to your website topic so that user can find more valuable information while he/she is reading your content it’s like your educating your user.
Website Speed: More than anything website speed is a ranking factor for any website to stay alive your website should load within 1 sec to make your user stand on your website for a long-time, stats say that a user get frustrated and will leave your website if your website loading time is more than 3sec.
Schema code: Having schema markup codes for your website is a big benefit as it improves your search results and makes it rich for a user visibility.
GA code and Webmasters: Having Analytics code and webmasters code in your website helps to track your website performance and the visitors who are visiting your website from different locations.
404: Having a custom 404 helps your visitors to understand that their no such page exist, you need to add your home page or services page link on your custom page so they can navigate your website easily.
301: Having a 301 redirection in place helps your website from duplicating the content and redirecting users to the preferred pages.
Canonicalization: Both 301 and canonical tag are of same use they help visitors to redirect to their preferred version of the page, this tag helps Google to understand which two pages of your website is most preferred by you and the user.
Well this are the techniques performed by SEOs to improve their website performance in Google, but if you want to know how to this are done they you need to check this tools.