I'd suggest forgetting about "hot trends," and instead focusing on finding problems that lots of people will pay you to solve for them.

Here are some ways to get started:

(a) Have a clear idea of the few areas where you may have a view of what lies just beyond the edge (technology evolution, market needs, etc.)

(b) Identify problems that need to be solved, preferably using primary research (i.e. talking to people).

(c) Remember that sometimes people cannot easily articulate what the problem is, so understanding what the problem is might require some effort.

(d) Figure out if the problem is big/widespread enough that it is worth solving.

Once you have identified a couple of interesting problems worth solving, I'd suggest doing these three things to narrow down the field:

(a) Try to sketch the business model for the startup idea (referring to Business Model Generation - Canvas)
(b) Get good at doing quick and dirty market sizing of opportunities
(c) Check if you are passionate enough about the idea to potentially spend the next 5-8 years of your life in making it successful

Based on a collective evaluation of the above, you might be able to zero in on a small number of ideas to investigate further (e.g. building a prototype, customer development, etc.)

Happy to brainstorm your winning idea resulting from the above exercise, if you'd like to.