Good luck finding a rental that is a manual.
Honestly if you daily drive a car for a week straight that's a manual, by the end of that week you'll be pretty good. Also, every car is a little different so just because you learned on one doesn't mean you'll still be good on another. When you're first starting to learn, you WILL stall it at a stop light, and the main thing is not to panic..
For me, it was really imperitive to understand what was happening when you release the clutch, so I'd suggest making sure you understand what's actually happening.
People make it out to be a lot harder than it is. The only way you'll get good at it is to do it.. I've tried to teach people how to do it, and honestly I think it's just as good to figure it out on your own. The only "teaching" you should need is for someone to explain what's happening when you release the clutch and press the gas and other basic do's and don'ts, otherwise it's all feel after that.
Both my cars are MT's, and there's times I get into AT cars and put both feet on the brake thinking there's a clutch pedal..
I don't even think about what I'm doing anymore.