The most important place of a watch hobbyist is his workbench. Of course, with huge investments, you can setup workbench of a dream, but without experience and dexterity, it will not bring you very far. On the other hand, if you have got some experience, you can also achieve good results with just a minimum of tools and space.
Which steps are necessiary on a (hobbyist) service, and how much time and effort they need, shall be described step by step here.
You can read about some important or unusual tools in a loose series.
For any watchmaker, datasheets are important, too.
And if you own an Android smartphone, you can look into the software area.