The biggest problem we face as new park riders or when advancing to bigger stuff is our fear causes us to want to slow things down. Speed is the hardest thing to maintain when you are apprehensive about committing to hitting a feature. My limited box riding has shown me that what Shred is saying is true. Speed offers an element of spatial stability and that translates to more stability on the feature.
Its really tough to make yourself do it and trust it. Take Shred`s advice and go to an easy, low consequence ride on box that you are totally comfortable with and just start lapping it at higher speeds. This experience will help you trust the stability offered by speed.
Yeah that helped me land my first boardslides. Going throughout the season with just my GF, I obviously didn't advance too much as she didn't know much herself, and was scared. It wasn't until I went with a buddy for the first time and he told me "just go faster, features will be easier". Having to keep up with him, because I'm not the type to be left behind, it quickly made me advance. It helped with everything from maintaining my carves better, to hitting features a lot easier.