Moving through an a space occupied by a creature (even team mates) costs an additional five feet. Thus moving through an occupied 5' square costs 10' of movement. Note that large monsters occupy more squares. Moving laterally through space occupied by a large creature costs 20 feet of movement. Moving diagonally through a large creature costs 25 feet of movement.
Moving diagonally costs an extra 2.5 feet per square. Thus, moving one square diagonally costs 7.5 feet of movement. To simplify the math, count the first diagonal as 5 feet and the next as 10 feet, etc. Moving diagonally across a solid corner (a wall, for example) always costs 10 feet of movement.
Jump over a prone body (normal sized) or a similar sized object costs an extra 5 feet of movement.
Heavy rubble and similar conditions count as difficult terrain. Movement is reduced by half unless covered by an ability.