Help with Google marketing allowing my website to rank high in google, attract more clients, ensure website is the best it can be

I'm looking for help with Google marketing to help my website reach a higher ranking in Google, attract more clients, and ensure that my website is the best it can be. Specifically, I am looking for help with SEO (Search Engine Optimization). I am also considering running an advertising campaign, though it is undecided at this time how long it might run for. If you have experience or knowledge in this area and are able to assist me in meeting my goals, I would be very grateful. Thank you for your interest and I look forward to hearing from you.