Yes, you can do this yourself, and for a small site the first year of it is a short list of things done properly rather than a long list done thinly. Most of what makes the subject look impossible is either advanced, obsolete, or written to sell something. The parts that decide whether a small site gets found are choosing the right queries, answering them properly, and making sure the pages can be crawled and understood.
Start with the queries, because everything else follows
A perfectly written page aimed at a query you cannot win, or one nobody with money types, is a wasted week. Look first at what your site already gets impressions for, then at what buyers actually ask you, and score the candidates on what a conversion is worth to you. Getting this step right is the difference between doing your own SEO and doing your own writing.
Answer the question properly and specifically
The pages that win for small sites are the ones with something first-hand in them: real numbers, real cases, the details a general article cannot include. Write for somebody who has the problem, cover what they will ask next, and stop when the question is answered. Length is not the point, and neither is repeating the query.
The technical minimum, which is genuinely small
Pages must be reachable and indexable, each page should have one clear address, titles and descriptions should describe what the page is, and the site should work on a phone. Verify the site in Search Console so you can see what is happening. That is most of it for a small site, and beyond that the technical work has a poor return until the site is much larger.
Keep a record, or you will do the first year twice
Which queries you aimed at which pages, when you published, and where things sat. Without it you cannot tell whether anything worked, and you will rediscover the same rejected keywords next spring. This is the part that spreadsheets lose and the part Longtailo Pro is for.
Questions people ask about do your own seo
Can you do SEO yourself?
For a small site, yes. The first year is a short list done properly: pick winnable queries, answer them well, keep the site crawlable, and record what you did.
How long before it works?
Months rather than weeks for a new site, and often faster on an existing one where you are improving pages that already nearly rank.
What should I ignore at the start?
Most advanced technical work, link schemes of every kind, and anything promising rankings. Also anything you cannot measure in Search Console.
When should I hire somebody?
When the work outgrows the time you have, or when the site is large enough that the technical side becomes the constraint. That is a capacity decision, not a knowledge one.