when i first saw no limits i had little knowledge of how to even use a computer, but i LOOOOVVVE wooden rollercoasters , and when the wood update came out i bought it. i was sooo confused by the program at first but after some trial and error, i made something that slightly looked like a wooden coaster after that i was hooked.. once i saw how awesome it was i just kept working along at it... even though my rollercoasters aren't the best, i'm proud of them.
just build things you like, and think others will like, be as crazy as you want, but keep things like smoothness, g forces and realism, in mind. post them here and many people will be specific about what can be done to improve the ride . then , build another coaster with those things in mind. after a while you might pick up little tricks of your own and you can save them to be used again or improved on.
the most important thing is to keep building things YOU like, other than that i can't answer such a general question...have fun ..