Check the results yourself using the same keywords. Look at the search results and
What automated tools do you use? You want a company that uses lots of tools and not just one, because one tool is likely to leave a digital footprint that are can detected.
What regular reports can I have that tracks progress? Insist on a progress report on a monthly basis showing your rankings and work done.
What keywords are best for me? They should have a good keyword tool that analyzes not only your website but your competitor’s website as well, to determine good keywords for you. Do you participate in link farms?
They should understand what you mean and the answer should be no.
How long will have to wait to get reasonable results?
90 days should be the norm.
Will you educate me on how I can contribute to your SEO efforts?
Do you participate in link-exchanges or reciprocal linking with other websites?
The answer should be NO – link exchanges are old hat and don’t work anymore.
What content would you like from me?
Every SEO should welcome you supplying them content because it makes their job easier. If they are not interested in receiving content from you, then you can assume they are using Black Hat spammy techniques, which exposes your website to the risk of being delisted or sandboxed. This is especially true if your website is under two years old.