Well, I just did it for the first time...you guys can post your work..I just wanted some advice or to get to know any of you that are good at it.. please don't mind the random thickness...I did that purposely..
Thicker lines in various areas help to convey depth. And it's not bad. I've learned that it's basically lots of practice to work on where to put thicker lines and also to get lines straighter and looking like you want them too. What tools do you use? Do you have a tablet and do you freehand the lineart or using the pen tool?
Tablets can be your best friend if you let it. I use a tablet and I definitely suggest you plug it in and try it out. Don't even draw with it yet, just use it for whatever you normally do on your PC. Doing things like browsing the internet, checking your email, and anything else with a tablet helps you get used to how it moves and works and improves your overall control. Then when you use it for drawing, you have a firmer grasp of how it works and to compensate for differences. Also, work with the pen tool, but once you get used to your tablet, I find it easier to line freehand. Again, it's something that takes time, practice, and a willingness to learn the tablet for the benefit, but I've found it so far to be worth it. Best of luck and throw me messages on here or dA (in my profile) if you have any questions. I'll do my best to answer them.