Different things you do with Waze -- driving, reporting, editing the map -- will earn you different amounts of points. You can get more points either by driving more or by updating the map for areas where you already drive. The Editor level is only depending on the edits you make, not your points from driving.
All Items on the map are locked. You can modify items upto your own lock level, but can always ask for a down lock, so you're able to perform the update you wanted to do.
It is possible to request the next editor level before reaching a certain amount of edits. In the BeLux it is difficult to reach the amount of edits necessary for automatic promotion to the next levels.
Starting at L1 you reach automatically L2 after 3000 edits and L3 after 25000 edits or on request. Higher levels only by request / assignment. The editor level is shown above the Feed in the Waze Map Editor. See the picture above. More on editor ranking see the Belux Community Levels page.