The types of skills you need to be good at discrete event simulation modeling are:

1) Process mapping: Discrete event simulation models are largely about process, so it's important to be able to map out a process effectively. In particular, finding the balance between level of detail captured and relative importance of the detail.

2) Basic logic skills: Much of the software out there is graphical, but you do have to be able to handle if/then logic at a minimum.

3) Data handling skills: This is often overlooked, but a key thing about being a good simulation modeler is using data to parameterize your models, and then to interpret the vast amounts of output data that the models generate.

4) Practice: Simulation modeling is a bit of an art and a science. Rarely are simulation practioners able to develop a good, validated, and useful models on their first or second attempt. Start small and gradually build up complexity.

We hope that helps. There's no better way to get started, than to just start working with it.