DeathMatch Maker II (Dmm2 from now on) is a commercially-available level editor for Quake 2. It lets you build your 3-d level, then compile the map with the quake utilities q2bsp, q2vis and q2rad. It is not the only editor on the market, and not the best by far, but in my opinion it id the easiest to use.

Advantages:

• as mentioned, easiest interface making maximum use of click and drag
• can divide map into levels which on larger maps is big productivity gain
• very easy click-and-drag operations to build your own prefabs
• reasonable collection of supplied prefabs
• toolbox has useful tools, making operations such as joining rooms together easy

Disadvantages:

• severe lack of detailed documentation
• not supported
• bugs in original release, although many fixed in 2.1 patch
• very inefficient texture manager
• no vertice or point editor directly

No extensive tutorials here as these are avialable elsewhere (see links below). However, here are some tips to help you on the way:

• Apply the 2.1 patch from the links below, which fixes a lot of bugs including a lot of the entities which don't work in the original release (doh).
• For any map other that a 1-room arena, the use of level is strongly recommended. Will help you focus on the room you are working on, not being distracted by all the clutter from other rooms.
• For faster texture texture editing, identify only those textures or texture directories you will be needing and move the others to differnet directories so that Dmm2 will not see them. This will speed up the texture manager no end.
• Don't overlap brushes. The documentation says that overlapping brushes won't appear on the map in Quake. They do, but they do not appear on the 3-d walk screen in Dmm2 which makes applying textures on them a tad tricky.
• Make maximum use of prefabs. For basic shapes that will be used heavily in your map, e.g. angled wall corners, create the object by itself, apply textures then drag into the prefab file you have created for that map. This will save time - believe me.
• Use wireframe mode in the walk window to move, then full texture view when applying textures.