Finding new content topics can be challenging because you want to ensure you're finding topics that have the potential to attract new customers and drive inbound leads. There are a few things to consider during this process:
First, consider the keywords you want to rank for and the intent behind them. What are people searching for when they use those keywords? Next, take a look at what your competitors are ranking for. What topics are they covering that you're not? How can you fill in the gaps and provide even more value?
Finally, it's important to ensure there’s enough search volume to warrant writing a piece of content around a specific keyword. For example, if you want to rank for the keyword "SEO tips," you'll first want to ensure that people are searching for that term and that it's not overly competitive and hard to rank for.
This article by Practical Ecommerce dives into this topic in more detail and explores some helpful SEO tools that simplify the process.