Here are two polyline power tips to help make polylines even more awesome!
POWER TIP #1 - Polyline grip editing: selecting a polyline, and then moving your cursor to a grip box will cause a mini menu to appear, allowing editing functions: add vertex, remove vertex, or convert to arc!
POWER TIP #2 - Sub-segment selection: Holding the [Ctrl] key while selecting polyline segments allows sub-segment editing!
Of course, you can also use PEDIT multiple, with JOIN option to make multiple objects into a single polyline.
Polylines are versatile objects! I hope you take advantage of these power tips in your drawings!