First you need to get signing setup properly. This topic is covered in many places and my recommendation is to use the Stericson walkthrough or the Stericson auto-signing setup tool. Once you can click on any zip or apk file and get the option to Resign it you are ready to proceed with making your own theme.
1. Download an archive manager that allows you to open archives inside of archives without creating new windows. My recommendation for this is the application 7-zip. It is tiny, free, easy to use, and on all my computers it has replaced winzip and winrar.
2. Now take a blank theme from Stericson to use as your starting point, this will be the minimum needed to change your theme and will contain all the original artwork.
3. Open the update.zip and inside are typically 3 files, framework, system or app, and META-INF. Leave META-INF alone, you wont be touching that. Inside framework and system/app is where the files are that you can change. In this case we will open update.zip, then double click framework and then double click framework-res.apk (this is where the next archive will open inside the same window, your life just got a little easier).
4. Now you are looking at assets, META-INF, res, and a couple other random files, the resources.arsc can be edited but I will show you that in another tutorial. Now open up the folder res and you will see the treasure we are searching for, folders with the name drawable. All of the folders that start with the name drawable are where we can edit the themes, this includes drawable, drawable-land, drawable-port, and drawable-finger.
5. Now drag and drop the folders drawable and drawable-land onto the desktop. Once they are on the desktop you can edit the .png files in those folders until you are ready to put your theme together.
6. Now in your still open window at \framework\framework-res.apk\res\ you will open the drawable folders one at a time and drag and drop your edited files into the archive, only dragging and dropping the files you edited and not just everything inside the folder.
7. Once you have your new images copied into the archive in the correct place you can just hit the close button or browse up a couple directories and find other files to edit. Any time you edit an apk and browse out of it or close it you will be prompted to update it in the archive by 7-zip (this is my secret shortcut), always press ok.
8. Now you have a freshly created theme ready to install, all you have to do is right click, chose to Resign the file, and once its done you can copy it to your SDcard, make sure its named update.zip, and flash your new theme.
Its literally that easy! And you use this same technique in the system/app folder to edit the apk files for the individual apps on the phone. Explore around in the update.zip and see what you can find, I only told you about the major items but there is plenty more to find and change. You can always copy a folder out of the archive and if you cant edit anything just toss it but if you can find something to edit, do so and throw it back in the archive. You guys now have all the info I had when I started plus all my tricks to making that process 10x easier.
