The easiest way to find keywords is by using Google Keywords Planner [free to use]. Alternative tools include [commonly used are] Answer The Public, Google Trends, Exploding Topics, and Answer Socrates.
The effective and likely result-oriented strategy to find keywords is by using any paid SEO tools which can help you with keyword difficulty/competition, and search volume.
P.S:
You are currently on the Digital Marketing Forum page; for more information on a variety of topics that may be helpful to you, please visit Blog Posts (button below) and also share any content post you love with your network.
[If you have any specific questions in mind, please drop a mail and I will answer through a post at the earliest possible time]. Check this forum frequently for fresh posts.