When you start new project then spend more time with making it do what you want it to do and less time fidding with free assets, particles or terrain.
Make it work with cubes and polish later with assets.
I see lot of people spend months on creating cool terrain instead of working sample.
Yeah, I am working mostly on 2d games and instead of looking for assets I just create some sprites myself in a minute and work on the controls till it feels good.