when i first started park skiing i was a little intimidated because other people were so good i was terrible. dont be afraid of what other people think, they were at your level at some point. committ to everything! this can be tough to do but youll be surprised by what you can do if you committ 100%. know you limits and dont push your self too fast. call out "dropping next" if youre about to go so you dont cut people or get cut off. if youre having trouble with a trick, ask someone in the park, theyll be nice and help you unless theyre an ass hole
the way i learned to do rails was just slide them stright on at first to get the feel or sliding. then one you get more comfortable with that, start to turn you skis a little more perpendicular to the box each time untill you are completely turned 90 degress to the box. keep you feet a little more than shoulder width apart and have some bend in your knees. make sure to commit!
for jumps, start on the smaller ones and get comfortable in the air. once you are, try some bigger jumps. practice skiing backwards before you attempt a 180