Learn on the go vs Learn and go

I often find myself taking so much time studying documentations of all tools I may need for a project before writing a single line of code . This comes form the fear inside that there is a better way to do things or that I use a tool and change it half road because it doesn't have XYZ feature (maybe I'm a perfectionist) .

This is opposed to other occasions -mostly when I'm pressed by time- where I just start writing code then with heavy use of stack-overflow and google I get things working .

I do believe in the idea that "make an ugly thing and update it with time is better than taking ages to make something beautiful" but can't manage to embrace it when approaching web-development or programming in general .

help.