Before you hire a SEO Agency, there are a few questions you need to put up. Let’s see what?

[Jacob]

[Richard]

Here are the things that you need to consider:
1. How many years have they been providing services?
2. What are the techniques they use?
3. Do they apply these techniques on their own website?
4. How much do you have to spend for measurable results?
5. What do other people say about them?
6. Are they going to help you sustain what has been started?
7. Are there any special promos or freebies that you can take advantage?
8. How good is their customer support?
9. Who are the people who will access or represent your website?
10. Are there any money back guarantee for extremely useless results?

Basically the main question is: why should you hire them instead of another similar provider?

[Profilic]

first of all you should check their own Google ranking for best SEO keywords. Then check their identity, quality of work and etc.

[Kim Cunnings]

If you're not too well-versed in SEO, perhaps it's not the best idea to be asking them intricate SEO questions, since you are not likely to understand the answers anyway.

I would simply ask them for samples of their previous work, and pay attention to whether the agency sees the bigger picture (how their SEO translates into your sales). Because it's not enough to just rank a webpage for whatever keyword - it's also important to see the bigger marketing picture.

And, I would ask for contacts of people who can recommend them.

By the way, if any SEO (specialist or agency) even says they guarantee you results, they're probably just snake oil salespeople - so, stay away !