How can i make my files upgrade proof for new features and fix releases.
I made a complete new package. Most of the times you see theme developers basing their theme on the “default” package. (you see a structure like app/design/frontend/default/themename/) In my case i made a complete new package like this app/design/frontend/response/default. meaning that if you want to make changes to the theme leave the default in tact. and only place modified files into for example app/design/frontend/response/yournewname/. This way you can upgrade the files and just compare what difference there is in your customized files. Be aware. Do not copy default and rename it. because then you would overwrite all files and a upgrade won’t have any effect.
If there is any question i can help you with. please let me know. Or e-mail me at firstname.lastname@example.org. Cheers!