yes, you must learn it yourself.
Most SEO charge way way to much and they have no real special tricks at all.
Just make sure you have
Original content
Good internal linking structure(make sure you link to your most important pages from every page of your site)
Write a good Title for each page (title meta tag)
Get as many one way links as you can with your targeted keyword in the anchor text.
Use H1 and H2 tags(although some top sites dont use h1 or h2)
If you just do the above you are 80% there to being an SEO yourself.