Map Flow

General

If a player can see it, they should be able to reach it very easily and without backtracking. Players should be able to get anywhere in a map very quickly.

Principles

No sharp edges

Nothing is worse than running with the flag and then getting stuck on a little decorative rock that looks so nice and pretty sitting there, but is a death trap for anyone that tries to run over it. —Hanover_Fist on the BeyondUnreal forums

Dead Ends have Rules

A dead end can either ruin or enhance a map depending on the situation. The worst thing you can do is force the hunted into an area of no escape and waiting for death while the hunter launches projectiles into the dead end requires no skill for the hunter and aggrevates the hunted. There are several ways to solve this:

Provide at least two ways through an area
Make the dead end quick to reach and retreat from
Balance the risk with reward

See the shield belt in Deck16 or the shield belt in DM-1on1-DavidM is an even better example.

Dead ends can provide a focus point for combat if they are used to hold control points and flag bases in CTF and DOM gametypes.

Use Sound Cues

Use water, health vials or triggered sounds to create sound cues near powerups or big guns; this makes the game a lot more tactical and introduces risk for reward.

Vertical Movement

Teleporters

This is the easiest and quickest way to send a player from point A to point B although it momentarily disorients a player, especially if your exit direction is facing a wall or fall. However, if you have a dead end that you just can't seem to physically connect to somewhere else, the teleporter can be a quick-fix solution.

Staircases and Ramps

The most common and easiest (and perhaps the best) methods for sending a player from one point on the Z-plane to another are staircases and ramps. Staircases tend to be much easier to build, but virtually require trim, are a pain to texture, and many times the polys of a ramp, due to the many surfaces. However, staircases may look nicer when done right, and as previously mentioned, are easier to implement. For smaller vertical changes, I use staircases. For larger ones or in other special cases, I use ramps.

Lifts

They use much less space than stairs and ramps and add a nice touch to the map, but don't use too many. A player feels "trapped" while riding a lift, as they can't move off of it until they reach the second point. Lifts require a player to stop and wait, which is never a good thing. Lifts are also much more difficult to implement and bot script. See also Lifts Vs Jumppads.

Jump Pads

Jump pads are cool and don't use much space. On the downside, they're a pain to bot script and require a lot of experimentation to implement. I also strongly recommend against using them for transversing longer distances, as this makes it very easy for players to miss the intended target. If you want to get the most out of them then read the Kicker page.

Warp Tunnels

These are perhaps the most difficult of the method to stick in your map. They require fancy architecture and texturing, multiple zones, and a bunch of experimentation in order to make them send your players the right way. On the other hand, in the right themes, these provide a very fast route from point A to point B, are generally cool (because not many mappers use them due to their difficulty), and give players the impression of moving very quickly. Also, they provide a fast getaway in a CTF game, like CTF-SkaarjOutpost.