Most stone kitchen countertop installations go
Be sure of what you want and express that clearly
If you're already decided on the countertop that you want, be sure to say that clearly to the fabricator. If you want black granite or you don't want seams on your granite kitchen, make sure that the fabricator understands that. That will narrow down your choices and options. If you don't like what's being offered, say so. Don't be afraid to voice your opinion.
Though you should stick to what you want, you should also listen to reason. If the fabricator says he can't do it but offers alternatives, you should also give it a listen. This is so you have a different perspective and a backup in case you can't find any other contractor that can give you what you want. It may be the case that what you want is indeed impossible.
Ask questions, and listen to the explanations
In every estimate, you should ask for the details and the pricing. You should also ask why an item is priced in such a way. That should let you compare other estimates, and also know why one estimate can be higher than others.
Follow up, but know the schedule
Fabricators would always give you a timetable. You can find there site visits, the timeframe for tinplating and cutting, and the actual install date and time. It's good to follow-up from time to time to be updated whether you're behind or on schedule. It also prepares you for any delays or issues that may arise. But even so, you don't have to call in everyday. You should give fabricators space to work. Time spent on the phone with you could have been time spent on the project.
Ensuring that you and the fabricator is on the same page is essential for any stone kitchen countertop installation. And the best way to do this is through proper communication. So be sure to be clear on the details, and don't be afraid to ask questions, and be always open to reasons and suggestions from your chosen fabricator.