It was taking a long time for my website to appear on Google search results, so I submitted my website to them every day until it was listed. After some initial success, my website is now quite difficult to find? Have I been penalised for over submitting my website?
If you use the website submission tool to submit the URL of your website to Google for crawling, it doesn't matter how many times you use it. You can submit your URL 100 times a day if you want too. It won't make any difference to when Google crawls your website, but you won't be penalised in any way unless you use some kind of automated tool or software to achieve the submissions.
Does Google penalise websites for over submitting? No, not at all. However, the effort you expend on submitting your website to Google and worrying about being penalised would be infinitely better spent on improving the content on your website. After all, it's the content that will bring you traffic and visitors, not the submissions.
Please remember that Google is a crawler based search engine. It will likely crawl your site eventually whether you submit your site or not. Once it has, it will periodically crawl your site again for the liftetime of the website, without any further intervention from you. You must therefore concentrate your efforts on ensuring your website has lots of top quality content for it to index. The more unique and genuinely intersting content you have on your website, the more likely you are to achieve the success you want on Google.
So, you won't be penalized by Google for submitting your site to often. However, you also won't benefit from it in any way.
Concenrate on your content!