Invisible Whirlpool to Cove:

Normally to reach the village of Cove, you need to either find the whirlpool or use the balloon. There is an invisible whirlpool not shown on the map that never moves, allowing easy transport to Cove. To reach the invisible whirlpool, sail your ship 19 squares north of the village icon for Paws, then sail 28 squares east. If you have a sextant, the spot is at 127 latitude, 125 longitude. Just sail there and you will warp as if you found the whirlpool.

 

Kill yourself to get an unlimited supply of anything:

When you die, you end up back at Lord British with 400 GP. If you have more than 400 GP when you died, you lose gold, but if you have less than 400 GP, you make a profit. This effectively allows you to buy as much as you want of anything that costs 400 GP or less simply by killing yourself. One easy way to take advantage of this is to go to Buccaneer's Den, spend all your gold (on herbs or items), and kill yourself on the HP-draining tile in front of the Guild. You will resurrect in Lord British's room. Simply return to Buccaneer's Den and repeat until you can't carry any more of the things you want. This is especially useful for the expensive reagent manroot. There are also a number of pieces of equipment that cost less than 400 GP (Sling, Axe, etc.), and the same tactic applies there as well.

 

Max your stats quickly:

Here is a surefire way to max out your STR (Strength), DEX (Dexterity), and INT (Intelligence) stats very early on in the game. First you need to acquire the Key, so go and acquire the 2000GP needed to get the Key and buy it ASAP. Once you have the Key, go to Castle Britannia and use the Key to open the secret door that leads to the entrance of Dungeon Hythloth. Upon entering the dungeon, immediately cast Exit and you will be taken to the dungeon's remote entrance (on Fire Island in SE Britannia). Reenter the dungeon from this point and then take one step forward and one step to the left, where you will find a Magic Ball. Anyone who touches the magic ball will receive a +5 permanent boost on his/her stats, however will also take 600 points of damage, so chances are the toucher will die if their HP is 600 or below, but the stats will remain. Do this for everyone in your party until your main character is dead and you are all resurrected by Lord British. Then return to Dungeon Hythloth via the secret Castle Britannia entrance and repeat. You can do this as many times as you like until each character has their stats maxed out at 50 a piece.