A friend of mine referred me to a realtor in Markham. He is really helpful and gave a lot of useful information. He also helped us find our first house in Canada (first the rental condo then to buy one as well). He is a fantastic person. PM me in case you guys want any specific information.
Read reviews online and check their websites/social media. Also you should interview 1-2 Realtors before you decide. Sometimes it's more about a Realtor's style of working... that will make you comfortable and confident to work with them. There are 54,000 Realtors in Ontario - you just have to find 1 good one that can help you.
There are a lot of unethical realtors in the market. Interview few and hire someone who wants to work for YOU and not just there to fill his/her pocket. See their work style before signing any contract.Check their knowledge about the market and neighborhood. Also, you would want to hire someone who will be there after the transaction as well.