Please don’t take this as whining, I love my unis, and enjoy them thouroughly. The problem is, I’m not making a ton of progress. On Muni and my 36er, I do ok, but on my 20, I can’t land diddly squat.
list of things I’ve worked on but cant land-
wheelwalk
SIF
Pedal grab
Crank grab to rubber
unispin
crankflip
any height on my hops
etc etc…
I’ve been riding for around two years 
Could the fact that its a Sun be holding me back? has anyone else had issues?
The unicycle could possibly be holding you back, but maybe not in the way you may think. I know for me that when I upgraded from the square taper Nimbus that I had to a KH it was a humongous confidence booster. The uni was pretty much the same device, but I felt so much more at ease trying harder things on it. Don’t get me wrong I’m still no pro. I can crankflip, 1spin, 3spin, hop up a 4 (5 on a good day) set, wheel walk, etc. I don’t have any super complicated rolls, or major sidehop or tech tricks. But with my old uni, even the stuff that I began picking up soon after getting the KH seemed impossible.
If I were you I’d consider upgrading your uni, and then picking one or two tricks to work on at a time. Be sure to break each down and take it slow. Oh, and consider making a list of the things you can do, even down to simple things like idling and freemounting. That was also a big confidence booster for me.
Hope I helped a little,
Max
Maybe try doing those same tricks on the MUni if you are more comfortable on that wheel.
Also giving the tricks a break and just riding for a few months can remove some mental blocks.
I focused on rolling hops, riding backwards and idling for quite a while and got nowhere. Gave up and a few months later when I tried doing them I was able to without too much difficulty.
you may be trying too hard.
practice, practice, practice, but don’t try too hard 
If you don’t have other riders around, it’s harder to learn new stuff. No one to bounce your progress and frustration off of, and no one else to motivate you to do what they just did. Also, no one to watch doing it in person.
Don’t blame the equipment. In the case of a Sun, if it’s still holding up it’s probably okay. With the possible exception of “poundy” tricks, where you might be taking it too easy in order to preserve your wheel. So go for it. If you need a new unicycle, you’ll know when it’s time. 
If you feel stagnant at certain skills, try others for a while. Or if you want to focus on a few specific ones, give them a certain amount of time each time you practice, and try to measure your progress.
I’ve been riding Muni for over 10 years and I can’t begin to compare my skills to the people posting photos and videos here. You’re often seeing the top riders here. I don’t let it bother me, I just keep on practicing. When I compare myself to riders of my own age here locally, I feel like I’m doing alright.
But the main motivation for me is to have fun and not worry about how good I am compared to others. If a particular skill feels fun or it might be fun if I can nail it, then I focus on improving that skill. If it doesn’t, then I don’t spend time on it.
Just keep concentrating on practicing what you enjoy, if it becomes frustrating, then back off and try something else for a while and come back to it later (if you want) and keep a large reserve of patience in store. Above all, don’t give up, just think to yourself, eventually I will land it, it’s just a matter of time. A positive attitude helps as much as raw ability, IMO.
It’s also really hard to see the progress of tricks if you work on many at a time. Try to focus on one trick. I like to pick 2 tricks that work completely different muscles, that way when I am tired from the one trick, I can still practice the other =)
Thanks for the advice. Today was a good day. I didn’t ride flatland/street/trials whatever at all today, but did some great Muni. I had been working so hard on landing stuff on my 20 and enjoying my new 36er, I had been neglecting my poor KH. So I decided to take it out for a ride, and man that was good for me. One of my best Muni rides, did some crazy DH. Every time I get on my KH, it amazes me. I rode well, and it reminded me of why I love Unis. End of joyeous post
Good! It’s important to step back and just enjoy it for awhile.
I only have been able to flip and spin for about the last 2 years. I would say it took me 6 months to really get crankflips down to the point were I could do them regularly. About the some with spins. its just practice practice practice. and doing it regularly…
its hard to describe… but any rider will tell you that when you are practicing there is that little moment when you actually stick the trick or get really really close where you know you did the trick right and you just need to focus on that moment. if you way seem to not be working. attempt to drastically change your style. you may even learn some things about doing the trick you didnt realize.
Don’t feel like you are alone. I learn slowly too… some tricks that I have learned I feel like I worked on for more than 30-50 hours at least before I landed once… and than I had to do double the hours to get slightly consistent.
Sorry if bad English I am lazy for everything today.
Im only really learning tricks and stuff on my uni last month or two and i have barely anything solid. Dont be discouraged when something isnt coming together for you, variety is great. Just dont lose hope
if im practising specific tricks on my 20" once ive spent time working on one or two and i get annoyed or frustrated i jus jump on my giraffe and practise some juggling. If that gets old/frustrating i might fly to the woods for some rolling jumps and speed runs on narrow trails on the 24", this is whats so fantastic about one wheel, it really is so much more than one wheel!!!
Don’t feel bad, I don’t know any tricks
Just do what’s fun, don’t worry about what other people can do, you ain’t them, so be you.
I’d love to know some tricks, but that would require practice, failure, lots of hard work, which, well, would take time and effort, of which I have none at the moment 
So just ride, it’s all good.
If you absolutely must learn a trick, then focus on that one trick, work with someone else who is learning the same trick, and sooner or later it’ll come, but seriously, uni is easilly one of the hardest sports to learn, so you need a lot more time, time, time
Progressing in unicycling is very much the case of fail, fail, fail, fail x 50 then all of a sudden “wtf I just did it”. That’s why you are finding it frustrating. Like others have said, don’t try to learn every trick at once. It’s good to just practise one or two new tricks, AS WELL as just riding casually.
I’ve been riding about two years and can do a good amount of tricks even though I’m a fairly slow learner. I also practice a lot and when I have time on the weekend practice 3-4 hours in a day. The key for me is enjoying practice and learning a trick becomes a side effect of that. Find the kind of riding and practice that’s fun for you. If there’s a specific trick you’d like to be able to do practice it 15-30 minutes (whatever you can do without getting too frustrated) and then do something you find more fun. I think it’s always good practice to ride as slow as you can (stalling if possible) as straight as you can. It took me a year and a half to learn one footed backwards riding!
+1 on 1-2 different tricks at a time.
You may want to keep a uni journal w/ long & short term goals. What you did that day, bests for the day (ie landed pedal grab, hoped off pedal grab to ground, did 2 times in a row, etc). On skills that take a while to learn it’ll be easier to see your progress when they are written down and you can see exacly when you did what.
SIF - For me I treated it like I was learning to ride for the first time. I went to a long rail and rode along it. It took me ~2 months before I could consistently ride the full length (~90 ft) on either side. I found it easiest w/ 114 cranks on my 20".
It could be good to learn and then hop on both sides. Then when in a trials line you can just hop up instead of having to turn around first. Also your holding hand wont get tired as quickly since you are alternating sides.
First you may want to get consistent w/ suicide mounts.
Before moving on to step 3, you may want to get consistent at revs (like a flip but your feet stay on the pedals.
any height on my hops - Improve your smaller hops ie hop up a flight of stairs w/ an exact # or w/o any extra hops, or a 1+ sec still stand between each, or 180 up/down each.