Jiufen (九份) is located at the mountains an hour away by bus from Taipei City. This can be taken as a day trip but I prefer no rush. A convenient way to visit Jiufen (as well as Shifen in Pingxi 平溪) is to take a shuttle bus from Ximen, leaving in the morning and returning after dinner. It used to be a small village with 9 families of local miners. The access was very tricky so every goods delivery was made 9 times for all the families. Fair enough.
Nowadays the village is one of the main tourist spots in Northern Taiwan and is crowded during holidays and weekends. When I say crowded, I mean it literally. Keep in mind the asian level of everything. If you decide to go there in peak days you cannot basically fit into the bus leading there. It won't even stop while full. It took me a while I found that out. Luckily there are several ways and several stations how to get there.
In my book, the main spot is a curve in the middle of the village framed by convenience stores as Family Mart and 7/11 on the other side, and the Dark Alley following the Jiufen Old Street (九份老街) between Jiufen Elementary School and the Jiufen police precinct, which is not really a street but stairs.
So what should you definitely try there is Taro Rice Balls made from a potato called Taro (芋头) – delicious, sweet and for some reason, purple. Another thing is mochi, chewy sweet cakes made of rice flour (麻糬) and green tea. Taiwanese tea is always strewn so don’t expect tea bags since it is a bad joke for them.
To recommend a hostel with the best view I have ever seen during breakfast is the First Stop Hostel in Ruifang District. For a low price you are gonna get full service, local advice whenever you need (not saying Taiwanese wouldn't help you in general) and especially, the accommodation with the only glass house in Jiufen to use.