This is generic advice, so it may not be applicable to your particular situation - but this is something that's served me well in Workforce Planning and Analytics:

1. Do a current state analysis - for a given topic, look at how things are today.
2. Extrapolate existing trends - look at the changes that are already occurring, and extrapolate these into the future. This will identify unsustainable trends that usually mean that topic is going to be disrupted.
3. Do an environment scan and look at those PEST factors (Political, Environmental, Socio-Economic, and Technology factors) that may have an impact on your area of study.
4. Of the factors from point 3 above, identify the two factors that both a) have an uncertain outcome; and b) will have significant effects on what you're studying. Note that this is not a risk matrix; risk matrices score factors on likelihood and impact - here you are scoring on uncertainty and impact. A factor that's uncertain and would have a high impact, for example, would be an election result where the two parties have significantly different policies that directly impact your area of study.
5. Create a grid of those two factors - and think about what would happen in the future (whatever your timeframe) in your area of interest in each of those scenarios.
6. Find commonality in those four scenarios in terms of how the world would deal with each of those scenarios; and you may have some insights into future events in that space.