Part 2 by slowboyfast : Composition & Graphics If you don't want to go too far into skinning and are okay with the standard interface, the first link hereabove might satisfy you, specially CUI's specific options.
This first part intends to be an overview of the whole thing a second part made by slowboyfast will guide you through a step-by-step on how to create graphic elements only with foobar2000's drawing functions and a third part by cliffflip will propose detailed presentations of some customization functions. I also recommend to read this good tutorial (though it's partly based on outdated PanelsUI), maybe this less developed one, some of the very useful HydrogenAudio's forums and the few links I'll drop here. I invite you to try and see by yourself, to keep in mind that errors come all along and to share any advice, question, difficulty or anything you want to say, may you be new or expert. I'm not an expert on the subject, I've started by installing a few skins and trying to understand how that worked I still think it's the best way to get a good handle on it, though a long and sometimes frustrating way. I've been asked to write a tutorial on skinning foobar2000, because many f2k users encounter difficulties modifying skins or simply using them. All credits belongs to Markkoenig (the original poster). This is the re-uploaded version of 'How to Skin foobar2000 Part 1' projects.