The right technique
Before vacuuming, pick up everything that is on the floor – socks, chew toys, Lego, et cetera! This will save you from having to constantly stop the vacuum and move things around as you go.
Next, start your vacuuming session by using your crevice tool to go around the perimeter of your room, pulling debris from corners and out from around furniture. If you don’t have a crevice tool, this isn’t essential, but it helps you reach areas that your vacuum otherwise couldn’t.
Finally, you should vacuum your carpet twice, once horizontally, and once vertically (imagine that you are essentially creating a grid on your carpet). By going over your carpet twice you will get better results and ensure you haven’t missed anywhere.
When it comes to frequency, in almost all cases weekly is going to be enough. High traffic areas like hallways or rooms where children and pets hang out might need an additional vacuuming from time to time.