I'm planning on developing my own web 2.0 application from scratch, using Yii Framework, JQuery, and HTML5 Boilerplate or Boots Strap. But I have huge dilemma. To begin this web 2.0, where is it best to start ? I've already completed flowcharts, diagrams and descriptions sheets for my project; However, i'm stuck programming and design wise. Should I start with the CSS of the the website, Photoshop, or functionality ( Php ) ? Where should I start ? I would really love this start up to be a success. I will greatly appreciate some responses.