1. The right mouse button was strongly implemented. It has many uses:
a. If you click the "fingers picking gold" icon (or press the P key), you go into "pilfer" mode. Ofttimes you would like to take that back. To do so, right-click.
b. If you are in front of a guild, shop, inn, or temple, you needn't type the name on your map if you should want to note it. Once outside, you need merely put your cursor over the door and right-click. The name is then printed on your city map. You don't want to go wild with this, however, as there is a limit to how much notation the map will accept.
c. Right-click often acts as the Enter key. If you are saving, after you select the slot in which you want to save and have a name you can accept, right-clicking finishes the job. If you are bartering, after you type in your offer, right-click and you get your response. As it happens, right-click also works on the buttons, so you can in fact confine yourself to right-clicking when you are bartering. It doesn't help you get full price in the game, but you can get through the bartering process more quickly if you use one hand for typing numbers and the other for the mouse.
2. Shift-C immediately casts the most recent spell you cast. For instance, if you are in a fight, you can re-cast "Light Heal" whenever you get low on health without mousing around and losing your fighting rhythm. Kill monsters faster!
3. If you find yourself outside a city and are completely lost and can't find your way back to the city, fast travel to it.
4. Outside a city, you can ask folks where the nearest dungeon is. "Dungeon" is defined as any place you can adventure in, so that includes crypts, deserted towers, and whatnot. They are identified on your map with a reddish-orange dot. "Dungeon" does not, however, include any place on your province map (e.g., Stonekeep).
5. Locks need not be picked. You can use a weapon to bash doors and treasure chests open. You do however supposedly run the risk of damaging your treasure.
6. If your one and only weapon breaks, you at least have recourse to trying to beat your enemies to death. Using your fists counts as a weapon and does real damage to your enemies. Also, the better the gauntlets you have on, the more damage you can do. However, I don't recommend it as a usual thing because it was poorly implemented; it often causes Arena to crash even if you have the recommended amount of conventional memory under (genuine) DOS.
7. All menus are both mouse-usable and keyboard-usable. The highlighted letters on the primary menus indicate the keyboard option for selecting the menu option. In a list box, you can use the up/down arrow keys.
8. You can use the mouse to move your character. If you move the cursor to the edges of the screen, you will note it changes from an "X" to an arrow. If you click while the arrow is showing, your character will move accordingly. E.g., if you place your cursor at the top middle of the screen, you will go forward. You can move in every possible direction using these cursors. Supposedly Julian LeFay swore by this system. It never grew on me, but it has its moments. For instance, you can more easily make fine adjustments to your compass heading using these cursors; the keyboard is too touchy to do it with any accuracy (at least, mine is).
Note also that the rate of speed you move is governed by how far the arrow is from the middle of the screen. If you have the up arrow showing (i.e., it's in the top middle of the screen), the closer to the very top it is, the faster you will go.
9. When you are in a treasure list (from a pile of treasure found in a dungeon or from a dead monster), you don't have to click on the individual items to take them. Use the Enter key.