Recently I started writing up several lists for Ardboys. First I started by looking at my normal 2000 point list and seeing without changing them what I could add. It then occurred to me this might not be the best approach. Why? Because army list should be something that flows together and is built for its role. If you build it with sections that look like additions or subtractions, you might be passing up units that help your army for units that simply just fit. I know simple right, but you'd be surprised at how many players I see playing the same thing over and over again especially myself. At a certain point its ends up feeling like a elaborate game of connect four.
So delete everything you have and look at what models you actually own, sadly in my case that appears to be a lot (I really wish I didn't have so many models that barely see the light of day or paint). And if you take the time to create a list and play it, I think it really adds to your enjoyment and your opponents. Especially if you play in a small group that are stuck in their ways.