Here is a list of 7 most important on page fixes for your website

• Duplicate Content– The penalty rate due to duplicate content is perhaps more than any other SEO factor combined together. Most of us are ignorant that our website content can suffer the duplicity issue and do not bother to take care of it. The remedy to this to check the content once in a month and remove any duplicity issues.
• SEO Friendly URL Structure- Having a easy URL structure is important for your website. Neither the users nor the search engine robots like complex and dynamic URL structure. The website URL should be short and keyword rich and should clearly give an idea of the page to the user.
• Webpages should be optimized around a topic or keyword- You cannot stuff keywords in your website anyone. Gone are the days when keyword stuffing was one of the technique to rank the website on top. Keywords should appear in the page title, alt text, h1 but more important is that it should look natural to the readers.
• Optimize the site speed-  Visitors dislike a site which is slow and Google has strongly taken a note of it. To create a good user experience, it is important that the website speed is good. To optimize your website for speed you can use the tools like Gtmetrix and Pageinsighttools, which give you a clear idea of what is the speed of your website.
• HTTPS Encryption- With Google constantly emphasizing the importance of a secure and encrypted website, you should implement SSL on your website. Many big websites like Wikipedia have already implemented the SSL which shows the significance of having a secure site. Many SEO experts believe that SSL is the new rankings factor in the Google Search Algorithm.
• Internal Linking- While we always lay emphasis in growing natural inbound links in SEO, we often tend to forget the importance of internal linking. Having a proper interlinking is very important On Page SEO element. You should make sure that all your pages are linking to each other. You need to keep in mind that exact match linking is not a good idea. Instead you should use synonym or keyword variations in linking.
• Fixing the broken links- Broken links not only create a bad user experience but often result in increased bounced rate. While having broken links will not lead to Google penalizing your website, it does makes sense to check and fix the broken links regularly. There are many excellent broken link tools available freely online that can help you in finding and fixing the links.