The SEO industry is a relatively new and unregulated business. As all new business it has attract a large amount of frauds and scam artist that are focused solely on making money. Not on providing a good service to their clients.
The business is also saturated with SEOs that have learned the profession from self proclaimed gurus that sell cheap courses online as a way to make money. These guides often teach you methods to game the system and see quick results. This results works for a time but the methods seldom works for long and once the search engines find out about the method they are likely to punish the sites that have used them. A good SEO will use methods that provide long term success without trying to exploit the system.
Many self proclaimed gurus that sell books have been in the industry for less then a year and are selling SEO courses because it is an easy way to make money. They are novices scamming beginners.
Your goal should be to find an experience SEO that provide a good service that will bring long term results.
Word of mouth
Word of mouth can be a good way to find a good SEO. Perhaps you know someone who have hired a SEO in the past that you can ask about their experience. Never trust the recommendation if the work has just begun or if it has just been finished. It takes time to see the full result of SEO work and if someone has just begun work they might be able to show good results because they are using harmful methods that will hurt the site but that initial produce good results. Only trust the recommendation if the person in question has worked with the SEO for more than one year.
An experienced honest SEO will never guarantee any results or any timeline for when you will see progress. An experienced SEO knows that each case is different and you never know exactly what it will take to get to the top. They also know that it will take 6 months before you see the full effect of any work. This means that it will take 6 months before you see the full result of work done during month one. It also means that you are going to continue to se results 6 months after the job was concluded.
I would never hire any SEO that is willing to guarantee results or offer you a deal where you pay them only if they deliver a certain result. This will encourage the SEO to use black hat methods that will bring fast results but that will have a long term negative effects. They will get your site to the top and make you pay them. Then a month or two later the site will fall into oblivion.
Choose a SEO that says that he can not guarantee any results. A SEO that explains the service he is offering and that focuses on long term benefits, not short term gains.
Most shortcuts and potentially dangerous SEO methods involve different types of harmful link building. These methods are very popular among bad and fraudulent SEO “experts” because the are easy to use and often produce quick results.
Asking a SEO about link building can often tell you a lot about the SEO. Ask him about how many links he can build each month, how many links he will build each months, where he will builds the links etc. These question will allow you to be able to avoid 90% of all bad SEO:s.
If the SEO tells you that ha can build however many links you want or if he tells you that he will builds hundreds of links towards your site then you know he is no good. A good SEO will tell you that he does not focus on the amount of links he build but rather the quality of the links. He will tell you that it can be damaging too build too many links too fast and that he will focus on building a few links each week. Exact how many links he wants to build will depends on how many links your website already have but the answer will usually be that he will build 10- 20 links a month or fewer. Some SEO focus on link baiting. This is a good techniques but means that he will not be able to predict how many links you will earn.
Only bad SEO experts will tell you that they will build a large amount of links.
The question about where he will build the links can also be very convincing. If he says he will use blog commenting, forum signatures, wikis, , private blog networks (PBN), social bookmarking or web 2.0 properties then you should not use him. These are other fast methods to earn a lot of links but they provide very little long term value.
A good SEO will say that he will reach out to and place your links on real websites or blogs.
The price can often be a good indication of whether a service is good or not. If a service seems too cheap to be true then it likely is too cheap to be true. No experienced SEO will offer to bring your website to the top of Google for a few hundreds and no one will sell you a quality link for USD1. You can find these services but they are all worthless as best and harmful at worst.
A good SEO will charge at-least USD50 an hours. If you pay a monthly fee than this will vary depending on how much work the SEO is going to do each month.
A quality link is likely to cost 200+.