What should we be sure to see and do?
I've only been to Lanzarote and we thought it was such a beautiful and varied island.
No really major sights.
Which islands are you visiting?
Lanzarote has illuminated caves and some hot geysers.
It depends which island you are visiting
With eight main islands in the Canary chain, it sounds like you need to get a guidebook to see which ones appeal to you and then decide how much time you have for your trip.