What a trail and experience! Some things to consider:
-Permits is the most important aspect for everyone. I tried for 4 days and got on a weekday. My advice is to try a weekday especially Monday on which I hiked . Less people on the hike as well.
-If you aren’t able to score, wait at subdome till 2-3pm or so. I didn’t see any rangers when I returned so I am assuming they leave at that time. However, the downside of climbing at that time is that your return journey will be in the dark. You can also try to ask other hikers if they have availability and many times you find someone.
-This is a strenuous hike! You should be in good condition to climb. Prepare accordingly. I climbed some local peaks of around 1000-1500 ft elevation before the hike and it helped. I also walked at least 7-8 miles daily for 6 days before the hike. To give you an idea of my fitness: I am 34 year old male with of BMI of 27 and I run 10k two-three times a week at a pace of 12-13 minutes.
-Get lots of water. I carried 3L or water in a camelback and two 875ml bottles of Gatorade and two redbulls. I consumed everything on my way back and still had a mile left to the car.
-I highly recommend camping in Yosemite. Hard to drive after such a long hike. I drove from San Jose and left the house at 3am and returned by 12:30am! It’s doable but would NOT recommend it. It’s dangerous to drive when you are so tired. So camp near the trailhead at camping grounds. You can also break the hike up and camp at Little Yosemite Valley which is after the Mist Trail.
-Pack appropriately and lightly. Don’t carry non-essentials.
-At first I wasn’t going to take trekking poles but my brother recommended them and they were SO USEFUL. Highly recommend to use some. I got cheap ones from Walmart and they did the trick.
-Don’t worry about bears. I didn’t see any. Wouldn’t carry a bear canister if it’s just a day hike as it adds weight. Just have snack and meal bars.
-Cables are tough! It involves a lot of arm movements more than legs. Gloves are a must! But it looks more scary when you look from far and are not that back once you start doing them. Take one log at a time and take your time. I took close to half an hour to climb with lots of stops and it’s completely fine. Go slow, plant your feet in a good solid way. You need good shoes - I used Altra lone peak 6 and they were great. I highly recommend them.
-Coming down from the cables - I tried both ways ie going face down or facing up and I HIGHLY RECOMMEND FACING UP. It’s SO MUCH EASIER. Trust me. You have more grip and are more stable plus you don’t have the fear anxiety that you have of looking straight down!
-I went up via the Mist trail and returned via the JMT. It adds a mile but better on your knees.
Those are my few pointers and I hope they help you. In the end, preparation is key. Break the hikes in chunks and have good shoes and lots of water. Take one step at a time and you will make it. Its absolutely worth it. Happy hiking!