Hi
I started unicycle about 3 months ago and now I can go as far as 800 feet but after that I fell down because my legs become so tire! Feel like jello! Keep practice until my legs get stronger? Will bigger wheel as 28 or 29 inch help me to go farther? I use my 24 inch unicycle. I need more practice on sharp turns. I still use sticks and learn to not use it! Hope to able to ride in dirt path in the forest presserve this spring!
Thank you and happy unicycle new year!
Good work you are doing well to get that far! I think you need to relax and focus on putting most of your weight in the saddle and only minimal pressure on the pedals. When I first started riding a 20" unicycle my legs would get tired from very short rides, but part of the problem was my seat was too short. You want your leg to be nearly straight at the bottom of the pedalstroke- so sit on your unicycle with the cranks vertical, and if your lower leg is bent you could try raising the seat.
At first when you are struggling to get your balance you tend to put a bit much extra force on the rear pedal and it fights with your forwards motion so it makes it much harder. Once you sit in the seat and relax, unicycling should take very little effort and you will need steep hills, great distances or intense riding to make you tired.
Good luck with your turns, they should come with practice. A bigger wheel will probably not be any easier until you understand the smaller wheel. You can never have too many unicycles so don’t let that stop you from buying more…
Every beginner is very tired from riding just a short distance. So yeah, keep practicing. It’s not so much to get stronger legs, rather you will learn to put more weight on seat - and it wouldn’t hurt to try that consciously. At this stage a bigger wheel wouldn’t help that much to ride farther, but with more experience: yes, bigger wheels definitely let you cover more distance. I notice I am just confirming what Rowan said but he is spot-on.
I started learning to ride 4 months ago. In that time I have ridden about 3 - 4 days per week on average, and probably an average of an hour each (very rough estimates). I have a 20" that I recently loaned to my nephew so he can learn, but I plan to get it back (I promised to buy him a 24" MUni or cruiser, which ever he wants, once he gets up and riding pretty well). It is a cheapie, but I like and plan to hang on to it. I also have a 24" that is actually the first uni I bought, but it was too hard for me to start learning on so I bought the 20", which was an excellent decision for me. I bought a 26" MUni two months ago and am really enjoying figuring it out. I just ordered a Nimbus Titan 36er that will arrive tomorrow or next Monday. So that makes 4 that I have purchased for myself. I also bought a 20" for my daughter and one for her friend, and they are both coming along great! Once I get the 24" for my nephew that will be 7!! 
. I will probably stick here for a while so I can get the MUni and the 36er figured out, which I suspect will take about a year of consistent work to gain a good level of proficiency on each. And of course, so that I don’t break the bank or make my wife wonder if I have completely lost my marbles. 
I started out in pretty good shape - I run and road cycle quite a bit. But this has really pushed the limits of my fitness, and I still get pretty exhausted when I am pushing myself hard. I am getting more efficient, but I still use more energy than I should. So what is the key? Just like you will hear over and over again on this thread - Practice, Practice, Practice! 
For me the real key is learning to enjoy practicing, especially when things are not going so well. Early on this was really hard for me, but now I can have a bad day and still find something positive in it, and can even laugh at myself and enjoy a ride that is less than what I wanted it to be. Sometimes you will have a great day followed by a terrible one. Pretty normal.
Keep it up and you will soon bust through whatever plateau you are currently stuck on! 
Thank you very much for great information!
To put it bluntly, drop the sticks. Chop them up into sawdust and hide that sawdust under a rock which you bury under six feet of dirt, forcing you to learn how to ride without them. You may surprise yourself with how fast you learn when you are forced to
As the others have noted, your tired legs are caused by you not putting your weight in the saddle. This comes with practise (and dropping those sticks). Good luck on your spring goal! Riding forest paths is one of my favourite things to do on one wheel.
One of the things that makes a big difference in going further is the ability to relax when riding. If you can ride without being tense you will find that you can ride considerably further.
Easier said than done though! sitting in the seat is one of the main ways to do this but it will not help off road, it is acheived by better cycling action and being more part of the unicycle; flowing in to corners and over objects.
Roger
We all go thorough this stage, and a small part of the answer is better conditioning. A much larger part of the answer is to relax and ride efficiently.
To rephrase Roger’s advice, “Become one with the wheel John”. 
Scott
The only thing I can think of is try to keep your arms as still as possible I know this is important for balancing when you have just started but try to use your hips as much as you can.
Thanks again! I only use sticks for start then drop and I go as far as 800 feet! Minkuni…good idea about to not use sticks! Bad habits and I will do without it! I think to practice without sticks would be on my grass in my backyard!
Relax, weight on seat and keep going is that what I will do for a few more weeks and I am sure able to go much farther! Plan to buy 26 inch unicycle for path in the woods! Of course…first smooth and flat path and growing!
It’s not so much being fit
Uni riding is great exercise and all. But going long isn’t so much about becoming stronger. Lot’s of people will advise putting your seat high (like on a bike, for better leverage), or various ideas to save energy. I guess if the legs are tired, they must have spent to much energy, is the thinking. I don’t believe it.
Uni riding is a strange activity, that is very stressful for new riders, even those in excellent shape. To run 10 miles, I would have to train a lot more, and become much more fit than I am now. Yet, I can ride my 20 , with the seat real low, as far as I want, all day until my ass is sore and I am not winded and my legs are OK. You just need to put in a few months riding. It is normal for your legs to go crap in a block or two when you start out. Just stick with it, it’s only real hard at the start. Then your legs will be fine, miles will come easy, and your ass will feel sore.
I think using a long wall, and smooth pavement is the best way to start. I have never used or taught anyone with sticks, so I can only guess you should ditch them, I concur with the general forum consensus that you should toss the sticks, in favor of waving your arms like you are an airplane.
I think it is a bad idea to practice freemounting on grass. Sure, if you would fall, you would not hurt yourself so easily. But freemounting is not about not getting hurt, but about getting on top of your unicycle and ride away. The riding away part is quite a bit more difficult on grass (for a beginner), and therefore I recommend to practice on a smooth flat surface. A gym floor is ideal, but asphalt or another hard surface is good too. Usually if the mount goes wrong, you end up on your feet. You might want to wear some protection if you are afraid of falling, e.g. wrist guards. Tips on freemounting are in the booklet Learning to Unicycle, that you can download for free from Tips for beginners (time for my monthly plug ).
Thanks for great tips! Smile!
Yesterday I broke my old record in distance … not that hard as before! Thanks! I did sharp turns little easier on my small driveway and I am glad that I did it!
Today is …#@&&@ 3 to 5 inch of #@#$%#@@ snow!!! Shoot!