Easiest thing to do is go into a dungeon and grind on the first floor by just wandering around the first room or two and kill as many monsters as feel like slaying and then head back up,this will give you a HP boast as the game awards X hp for each monster you slay(It was a left over from the Akalabeth code which Ultima 1 uses a bit of). and the monsters on floor 1 are easy as hell, This way you will have a good amount of HP,plus some loot for buying food, weapons,armor and transportation.

Of course I have a few for you. Here are just a few that will get you started strong.
First, the best character to start out with if you want to start strong is a dwarf fighter. Next, spend the basic money on a simple inexpensive weapon and food. Find a dungeon near a town. Go through the first level and kill the rats, thieves, and other weak enemies. When you leave, you will find you have gained hit points just by going through a dungeon.

While you are in the dungeon, if things get too crazy, find your way to a quiet place and press c. This will cast prayer and build either a force field or a ladder. Keep doing it until ladder up appears. If you are on level one, you will leave the dungeon.

Repeat the dungeon trips often and always try to stay close enough to a town to buy food as soon as you get out of the dungeon. Keep earning money in dungeons and you will be able to buy better weapons.

Look for castles and talk to the kings in them. Give them gold and they will sell you hit points. Offer them service and they will send you on quests. Some of these quests involve fighting tough monsters, but some kings just tell you to find a sign post somewhere, so you get a reward from the sign post (many offer goodies) as well as from the king.

As soon as you can afford a sea vessel of any kind, begin sailing around the world looking for signposts and other cities and castles. Always keep venturing into dungeons and you will become much richer and gather many hit points.

Soon you will find yourself very strong and able to take on any enemies you find, even ships and sea monsters.

A final note: Remember in Ultima I you are not the Avatar and you are not bound to do good in the world. Find cities with weapons and armor shops close to the entrance to the city. Go outside and save the game when you do. Steal and run. You should be able to get out of the town if you are quick enough. Some of the weapons you will find include light swords and laser blasters. Those do major damage against unsuspecting medieval monsters.

This should get you deep enough into the game where you can enjoy the deeper aspects of the game and really enjoy exploration.

Remember! The key is to use the dungeons to your advantage.

Thanks dct for you quick reply and thanks Zap for all those advice, I think I start over again because i dont know if i can do is without weapons.

If you can deal with a bit of tedium, buy a frigate as soon as possible and head for the outskirts of each mainland. The world is basically divided into quadrants and each has two castles and two signposts, bounce between those signposts and you can max out your stats relatively quickly. If you get low on food or cash, shoot some monsters with your boat.

You could consider that cheating, but I think anything the game is programmed to allow should be ok. Of course you could always take the hard road if you really want, or for the second go around or something.