Do you plan the application, on which you will be working, before you actually begin to write code?

I do web development and usually begin with something rough or look at designs of other developers. Like an dashboard example, when I see an image on google search that I like, I try to make something simmilar and when I have the surface I can add the functionality and improve the design.

Sometimes I have to make changes in half of the development because at the beginning there was no assumption that there will be a need for a certain functionality or I change a implemented feature to work properly, so I have to refactor something I made as a ground on which other parts will rely, although if I had planed the application in detail, maybe it wouldn't come to such refactoring.

In school we did prototypes, used to draw flowcharts and hold on a precedence diagrams that we made, but now at work when I receive an projekt I just begin to code :-D maybe this should change, how do you do it? If you plan your project, how do you do it?

I thought sunday will be the best day to read the dotnet documentation... at the end of the day I can honestly say I know all top rants now.