Can I do SEO on my own?

Yes, you can but I don't thin i will be efficient

Yes, you can do SEO on your own, but I don't think it will be efficient because there are a lot of aspects you need to know that are hard to learn on your own. Also, it will take you a lot of time. In my opinion, the best option is to use the services of a professional company like Serendipity Online Marketing. I used their services to improve the SEO of my online shop, and after one month, I started to observe a lot of new users on the website. Their services weren't cheap, but I think it was worth it.