I can give you guys the 5-minute short version.
First, throw out the existing feats, and instead, replace them with feats based on spell level, and one based on items that have a single charge. This reduces down into Create Single-Use Item (which replaces brew potion, and scribe scroll), Create Minor Item(which allows items with up to 3rd level spells in them), Create Moderate Item (which allows up to 6th level spells), and Create Major (which allows up to 9th).
If you want to place multiple different spells into an item (like a rod), you'll need the multi-spell feat, which allows you to do that.
Second, figure out which spells are requried to create the item.
Third, well, I can't really explain the third one without a lot of other rules, unfortunately. It'd be too hard to explain here, since there's just a lot that goes into making magic items.
One tip I would recommend is to calculate the cost of the item, and then require that the PC either acquire items to fulfill that cost, or to purchase items that equal the cost. I would never allow a PC (IMC) to just say, "Ok, I've scratched off 5,000gp" Part of the fun is to actual acquire and purchase the components needed for item creation.
Hope that helps, at least a little bit.
