Try to do things right the first time because each change usually means many changes. But you'll also need to learn to scan images, manipulate graphics, and carry out increasingly more complex functions. You will need to be very well organized and careful in your file management habits. Save your files early and often and keep at least two current back-up files on floppy disks. PowerPoint is a somewhat glitch-prone package whose large files sometimes push the capacities of computer and printer memory to the point of no return.
System crashes that eat files are frequent enough to warrant great care in file management.
Learn what you need to learn as you go along. Don't try to learn the whole program at once. Don't think you need to know everything to do effective work. Keep in mind that all design elements should have a purpose related to the message you wish to convey. Try to be flexible and open to multiple revisions.