Usage Instructions:

Unsaved Movement

Drag almost any normal UI Panel (e.g. CharacterFrame, SpellbookFrame, TalentFrame, QuestLogFrame, FriendsFrame, etc.) from any open space on the frame. This movement is intended to be for temporary changes and does not store location in the FluidFrames database.
However, this movement registers the frame as user placed. The position will be remembered by the WoW client and restored on subsequent login/reloadui if not overridden by placement code (e.g. CharacterFrame, Minimap). Most of these draggable frames reset if you hide and re-show them.
Some frames will not reset automatically (e.g. GameMenuFrame, BattlefieldFrame). To reset these, highlight the frame, right click to reset and then reloadui/relog.
The MinimapCluster is an added exception case and can be dragged by the top bar.

Assign a key-binding [Main Menu > Key Bindings > FluidFrames > Highlight Mouse Frame] to select, highlight and cycle through frames under the cursor. (The "Highlight All Mouse Frames" binding cycles through all frames under the cursor, including unnamed ones.)
Put your cursor over the frame you want to move and use the key-binding. It will select the frame the furthest underneath. Consecutively using the key-binding will highlight frames closer to the front. Hold shift while using the key-binding to cycle backwards through the frames.
Drag the highlighted frame to relocate it permanently. It will disable movement from other code sources and save across sessions.
Hold shift and drag from the sides or corners to resize.
Hold shift and drag the bottom right re-scale icon to re-scale.
Right-click to reset a moved/resized/rescaled frame once highlighted.

To drag some bars you have to drag the 1st button.
To move the primary action button bar drag ActionButton1.
To find the ShapeshiftBarFrame put your mouse over the left edge of the 1st button when using the key-binding.
To drag all the player buffs & debuffs make sure you drag the TemporaryEnchantFrame.
To move Chat Frames just unlock and use the default tabs.
To drag the TargetFrame make sure you don't drag the TargetFrameTextureFrame on accident.
To move the whole minimap drag the MinimapCluster.
Experiment with which frame to change. if it doesn't work the way you wanted just right-click to reset.
Some frames have complex sub frames that update their locations independent of parent size. If resizing doesn't work well try scaling.
If secure frames are moved by default blizzard code while in combat they cannot be moved back until after combat. Also, you will not be able to drag secure frames in combat.