As many reviewers have warned, this is not an easy hike. Very strenuous hike, but definitely do-able if you just take it slow.
The first one third of the hike is rather manageable, and brings you to a nice viewpoint with a perfect view of Half Dome. Walk another 20min more (part of it is downhill) and you will be greeted with a magnificent view of the Upper Yosemite Falls right before your eyes. The view is breathtaking and simply amazing. To the left, you see the falls, while to the right in the far distant, you see half dome.
Congratulations, you're now at the base of the upper yosemite falls :) From this point onwards, you will just keep climbing upwards until you finally breathe a sigh of relive when you see the sign saying you're 0.2 miles away. There, the most difficult part is over :)
Then you will start to go around and down until you see the falls. Theres a view point right at the end which is a little dangerous/ steep to get to, but theres metal railings by the side so it isnt that bad :)
We packed some sandwiches so we could enjoy our lunch next to the falls. After which, it'd be a long walk all the way back down again :)
I'd recommend starting early, about 8am and take your time to go up so by the time you're at the top, it is about lunch time :)
Bring plenty of water, we brought 2 litres of water each and it wasnt enough. And dont double book hikes on this day :)