YOu have to start with a RIP that will allow you the flexibility and tools to progress through the various steps.
You need a proper spectrophotometer like an EyeOne. Densitometers and colorimeters don't measure color in a way that works with an ICC profile.
You need software that makes the ICC profile in the final step of the process. This can potentially be the RIP its self. More often it is a separate piece of software that generates the ICC for you to import back into the RIP.
The over view of the steps go something like.....
1. make a new media model in the RIP (sometimes called a media profile just to confuse you)
2. establish ink restrictions for each individual color of ink (excluding light inks at first)
3. linearize...sometimes called calibrating
4. set your total ink value. Not all processes do this step at this stage. Some do it within the ICC only.
5. print and measure the ICC profile
6. setup the ICC behavior for substituting black for CMY, total ink, and where black starts being used relative to cyan.
voila! you have a media profile.
Expect to spend $2000-5000 for software+hardware and loads of time "learning" unless you hire a good consultant to get you up to speed quickly. A good consultant will run you about $1200-1600 per day and expect at least 2 days of training to be needed. Especially if you're just getting started, don't skimp on the training time.
Sound expensive? It is. But....if you are busy enough, it can be VERY easy to justify and the ROI can be weeks or a few months for a busy shop.