Coming to general methods of problem solving in recreational math, I always look for symmetry and transforming the problem from one problem space to another and induction techniques before attacking it. For a research/modelling problem, my approach is to start working on the most simplified version of it and gradually progress towards the original problem.
There is an excellent numberphile video on Josephus problem that illustrates how examining specific instances to observe patterns can help solve the general case.
https://www.youtube.com/watch?v=uCsD3ZGzMgE
Edit: Formatting