You may find the following commands and shortcuts useful within Ultima Online.

Right-click and hold: Moves your character toward the cursor. The farther away from your character you keep the cursor, the faster your character will move. 

Double-right-click: Pathfind. Automatically moves your character around obstacles and towards the cursor. You cannot pathfind through closed doors or around buildings.

Double-left-click (on doors or gates): Opens the door or gate

Alt-left-Click (on another character): Follows that character

Alt-left-click (on self): Stops following another character

Left and right mouse click: will "lock your running" so you don't have to hold the button down. 

Type what you wish to say, then press Enter: Your speech will be displayed on screen, directly above your character's head.

Ctrl+W: will repeate last sentence

Left-click (on a character or creature): Displays the character's name or the creature's species

Double-left-click (on a character): Displays the character's Character Window. Peace Mode Only

Tab-and-hold, Alt-C: Toggles between War and Peace mode

Double-left-click (on a character or creature): Attack that character or creature

Left-click-and-drag (on a character or creature): Displays a status bar showing how injured the character or creature is Left-click on item: Displays the item name

Left-click on your character: Brings up the context menu

Left-click-and-drag item: Picks up an item or moves the item

Shift-left-click-and-drag item: Moves an entire stack of items

Alt-shift-left-click-and-drag item: Picks up a single item from a stack of items

Double-left-click an item: Uses the item. If a targeting cursor appears, you must target another object on which to use the item.

Double-left-click (on containers): Opens the container and displays contents.

Double-left-click (on your character): Opens your Character Window Single-right-click (on a window): Closes an open window

Alt-O: Displays Option menu

Alt-K: Displays Skills menu

Alt-S: Displays Status menu

Alt-P: Displays Character Window (Paperdoll)

Alt-R: Displays "radar" map view. Alt-R a second time expands the window

Alt-I: Opens Backpack (Inventory)

Alt-J: Opens Journal

Alt-B: Opens Spellbook

Ctrl-Q: Repeats last typed text (speech or action)

Alt-X: Exits game

Alt-C, Tab-and-hold: Toggles between War and Peace mode

~ - gesture name - Enter: Executes character gesture. An example would be typing ~wave and the enter key to cause your character to wave. (Gestures are only available in the Third Dawn client)

Ctrl-Shift: Opens 'Handle' windows for any items/creatures/characters onscreen with which you may interact. You may interact with handles the same way that you would interact with the object they name. For example, double-left-clicking a creature's handle while in war mode will cause you to attack the creature.

Left-click-and-drag (window border): Moves the selected window.

Left-click-and-drag (window gem): Resizes the selected window.

Spin mouse wheel: Zooms the game view towards or away from your character. When using a non-wheel mouse, you may access the zoom command through the Options/Macros menu, or the Menu Bar. (3D client only)