I'm new at the field of computer programming and I chose to learn it at the University, but I have some problems with project management, usually before I write any code I start to plan it on the paper, and when I'm finished I begin to code, but I understood that usualy I write only 20-30 percent from my planning, and I change my code a lot, can somebody recommend me a good book or blog about commong pitfalls and troubles with software planning and management.