The best place to start your track is on a notepad. Think about words and emotions that you want to connect with it. "Melodic dubstep, sad, rainstorms, male vocals." Anything that comes to mind. Then write down what you want the focus of your track to be: Drums, Melody, Chords, Bass, Vocals (doesn't have to be these, but this is always a good starting point). The thing that you want people to remember your track for. If you can, start describing how you want those different elements to feel or any ideas for them that sprout from your word cloud - "dark drums, pure saw bass, huge chord swells, glitchy vox effects".
Now when you open your DAW, you'll have a perfect reference point for what sounds to grab, how to design your synths, etc.