SEO requires time, effort, and patience. Ranking improvements typically take 3-6 months, with long-term impacts lasting around a year. The beauty is that, if maintained, SEO rankings will be highly advantageous to you in the future, generating great ROI as time passes. The only bad option you can make in SEO is to do nothing at all.
SEO is like a snowball moving downhill. At first, it is little and slow, but as efforts rise and more SEO initiatives are added, the snowball grows larger and larger, eventually rolling down the slope uncontrolled.