There are several things that are unknown to starters that I can recommend:
- Newbies often don't get mechanism of SAY (something awaits you in port). When you see messages like "you hear distant bells" or "the bat flows to ship and die" and other, you may notice indicator on right corner of messages window. It means that on your next visit in port there will be more quest-like options in city. This thing happens when time runs and every action that requires SAY resets it. You'll easily get into it when you'll see.
- There are no really easy profitable trade routes at all. Some routes give you money to sustain yourself and small amount to grow, but forget about getting rich from trading in early/mid game. Some pretty profitable routes are too complex, best is involves surface and you'll need big ship, otherwise you run out of fuel and die in evil sunlight.
- At start you have nothing and don't know what to do. Do port reports. Actually, do it until end of the game. There is Admiral in London who gives you some small amount of money and fuel for every port report. When you visit port, always compile a report, it is free and not dangerous (except some special places, but they are rare). So, typical journey will be like "visit this, this and this, maybe discover something there, maybe buy something, but get port reports". Every route "circle" will give you some fuel and money to sustain yourself, although it isn't profitable. At middle of game, when you visit 5-6 ports at once, it becomes pretty good (at least for fuel).
- I recommend you to use your starting ship for long time, even if it slow and shitty. Cutter is fast but it is perversion of common sense and it has no storage space. Freighter is _slow_, and trade isn't too profitable. I completed most of game with starting ship (I upgraded some weapons though). I truly recommend to jump to frigate on late game, it is perfect.
- Don't fight with monsters, they are evil. Some are too evil, so they'll kill you easily with first strike. Don't do it. You'll fight them in late game much. Only few monsters actually have interesting (and risky) loot, and they aren't for starters. Like that ship-eating mountain. You saw ship-eating mountain? Oh, you'll see, you'll surely see. Also beware of the birds.
- Fuel: when you move with lights, you spend much more fuel than without it. But moving without lights... bad. More powerful engine also eats much. There are some quest-made engines that very, very good, so I recommend to stick with starting engine and replace it only when you'll get them. Yes, sometimes you'll be bored because of slowness, but it is meditative game. Slow, dark sea awaits. Remember: some places (related to hell) have cheap fuel, so consider next route with them.
- Supplies and crew. More crew you have, the more supplies they eat. But more crew you have, more secure you are. When you ship got less than half of crew, it couldn't run on full speed, and sometimes it is very dangerous (actually, it always very dangerous). So, balance you crew on level like "half + 2-3". On starting ship it isn't easy as on larger ships, but try. You can't just buy much crew you want (there options for 1 or 3 sailors in London for each visit, and many events). Be very cautious, try to maintain some reserve of sailors. Few unlucky events and your sailors go mad or eat themselves. Or you go mad and eat them. Or you doing it for purpose. Don't eat people please, it is bad.
- Terror. Another thing that not described much. When you move in darkness, it grows very fast. When you have "one light" (ship light, being near coast, being near buoy) - it grows slowly. When you get "two lights" (combination of ship light and coast or buoy), it stops growing and temporary bar goes down. So, if you plan your route carefully, you can combine your light switching and terrain to get best outcome. It sounds more complex than it is, you easily get this skill after few hours. Just look at your terror bar.