Still a noob too. But heres some of my thoughts.
Specialize your fleet. I started with "combat freighters" Mules, wayfarers, etc. and I think thats bit of a mistake. My playstyle is "scavenger/bountyhunter/high value transport/seigebreaking.. But, when deciding between 2 mules, vs 1 cargo ship and 1 destroyer... the 1/1 is better, because I can just deploy the destroyer into combat, and leave the cargoship out of it. theres no point in deploying weak ass half ships into combat.
buy/sell on the market seems not profitable due to taxes. but, the bar "I need x delivered to Y" payments did me well. as well as the occasional, pop up trade quest.
my fleet atm is, 1 Legion battlecruiser, 1hammerhead destroyer, 1enforcer destroyer, 2 condor carriers, 1 heron for combat. 2 colossus cargo freighters, 1 starline transport.
(atm, possibly a bit too carrier heavy. Carriers are easy to play, seem to be WAY more aggressive then most others in AI. but, are relatively defenseless vs assaults themselves. More ships in combat, means more distraction, and split firepower. While 1 ubership, can get focus fired upon. Granted, in the case of the Legion here... it IS more powerful then the rest of the fleet combined.. Pay close attention to supply cost, and fuel costs. Sometimes 2 weaker ships might be better then 1 more powerful. some "tanks" to distract for the carriers fighters to do their thing, might be a good idea here. A strat I might try is outfit my carriers with pure torpedo bombers, no fighers. Then, field alongside my carriers some mid range, high shield Frigates. these Frigates will be set to escort/defend the carriers, and outfited with LR (long range) energy point defense. To annihilate enemy fighters, and missiles. And also serving as a distraction to keep pressure off the carriers)
I hear best early game is to build a FAST explorer fleet. skip the combat ships, and just outrun anyone that attacks you. do explore missions to build up a cash stockpile. (I didnt do this.)
Equalize max burn. note on my fleet, most of the ships are 9 or above max burn. The legion and colossus are both 7. Giving each of them , the aug drive field mod, to get them up to 9 max burn is massive. 16 vs 20 max burn top speed for the fleet.
Abandoned space stations are FREE storage. I found that legion battlecruiser derelict pretty early. it was WAY out of my price range at the time. I had like 500 crew, and that thing is 1200 skeleton crew alone. tripled my fleet supply/fuel costs too. So I mothballed it, and took it back to civilization. I had no colony at the time either, so, had to store it. 5k upfront then was costing me 5k/month to store the damn thing. I did eventually move it to an abandoned space station when I found/realized it. And then shortly after to my colony, which I started a bit too early.
I had to put the Legion into action very shortly after that, as pirate raids on my colony were too strong without it. It could take out pirate bases.
Dont start a colony until you have 1mill credits, and a fleet that can take out pirate capital ships/stations.
Sensor str.
Easy to overlook. Sensor str is the top 5 ships of your fleet combined. They each of an innate value. you might see the apogee mentioned, it has an innate +Str hull mod.
This determines how far away you can identify other fleets, debris, etc. it is then further modified by pulses, transponders, etc.
Sensor profile.
Profile is also the top 5 ships of your fleet combined. Bigger/damaged ships have larger profiles. This is how easy you are to identify. Those colossus cargo are great for hauling, but are VERY easy to see, and would make sneaking up on pirates very hard.