As stated here, Revit enables you to rotate the view to align with any horizontal or vertical wall you like.

Revit also gives you multiple other way to align with or stand perpendicular to walls, lines, groups and a host of other objects. Sometimes this can get confusing and if you have many different directions represented in one drawing.

To make things easier when drafting, use these shortcuts to make Revit snap to the point you want:

Shortcut	Snaps To
SI	Intersections
SE	Endpoints
SM	Midpoints
SC	Centers
SN	Nearest
SP	Perpendicular
ST	Tangents
SW	Work Plane Grid
SQ	Quadrants
SX	Points
SR	Snap to Remote Objects
SO	Snaps Off
SS	Turn Override Off

This is, of course, on the basis that you haven't changed these shortcuts in the KeyboardShortcuts.txt file.

I have highlighted the ones that I think are the most useful.