Try out as many tutorials as possible, it will help immensly. Also after a bit of practice and you feel you can start to move on, decide what style of work you want to create i.e landscapes, sci-fi, abstract etc. Having one particular preference at first helps to focus you and improve your skills. After that you can branch out and try your hand at different things. Posting work in progress in the forum will help, and never be afraid to ask for tips or help, even the Bryce masters will learn new techniques from being here. Another tip is when you feel confident enough enter the monthly challenges on offer here as quite often they push you further and make you use bryce in ways you might have avoided before. Most of all have fun and keep at it you'll be amazed at what you can do with this software.

http://joevinton.blogspot.com/