If you are new to coloring don't be shy, remember everyone started as a beginner at some point. The coloring community is supportive and you'll soon find that you could be making new friends, picking up tips, learning new techniques and influencing others to crack open their coloring sets!
Blot, don't rub, with your eraser. Rubbing colored pencil will do more harm than good, grinding colors into the page rather than removing them. For more control and a cleaner page, press a kneaded eraser like this one on the area and then carefully peel it off, the same way you did with Silly Putty and the Sunday comics as a kid.