the only way you will get better is by practicing, keep these tips in mind...

first it needs to come natural (not forced, the harder you try i usually find the shittier it comes out) just relax, get comfterable, play wtih a paper and some weed/tobacco for while, just rolling it back and fourth, learning how to make the weed/paper go where and how you want it...

patients, you have to have patients, this is similar to relaxing and just lettting it come naturally, but in a diffrent way, rolling should take as long as you need it to take, if that means you need to roll all your joints in the middle of the night then do so, a joint you put your heart (so to speak) into rolling, will be much more satisfactory on an esteem level, and a 'factual' level.

a more important fact is the paper (brand) and the consitancy of the weed, you still want it to have body, but you also dont' want even minature nuggets in your rolling material, another is don't use cheap papers, such as bugler, even with an experienced roller it is kinda difficult to roll a bugle without it going out 100 times, getting the right conistancy is just giong to be trial and error, if your joint runs really bad (one side or one part burns up to an inch farther) it's either due to loosely rolled or it's due to you not grinding/cutting it up fine enough, if it goes out constantly, it's becuase it's too tightly rolled, the paper, or you grinded/cut it up too fine.