Whenever you get in game drops and loot. Take them back to ESD or a frieghter in space and sell the items to them. That usually nets the most Energy credits. Otherwise, press I for inventory. Then on the replicator there is a sell button and you can sell the items but for a lower EC then a vendor. Just keep doing this and the numbers will add up. There is a exchange on ESD where you can buy better weapons and other devices for your ship and your ground toon/bridge officers. If you at level 10 and about to rank up, wait till you get your teir 2 ship and get MK 4 items.
Whenever you find equipment which is rare or "good" (by any means) which player's can't by from an NPC, I would suggest you offer it at exchange. You can really get some money by sorting out items of value which you can't or just won't use yourself.
Sector Space is a lot more bearable when you get to RA or VA rank.
From there ypu can do the STF's to get the Borg kit (of which the engines allow for Warp 14 in sector space),
You can use emblems (or C-Store credits) to get the Advanced Heavy Cruiser Retrofit, which has the ability to transwarp to almost any Sector Block.
You got to think of it as the distance you are travelling. Ff it takes 30 seconds to travel the distance light would take 5 years to travel, you are going very quick!
(technically you are not moving at all, space is moving around you. but that is a whole other discussion.)
For good weapons (and making good credits) i would recommend starting on crafting. It is a must have for end game in my opinion and you can always craft items to sell on the exchange for some cash.
Off topic, but speaking of Sector Space, when trade ships (like the S.S. Azura) go to warp in sector space, what is going on there? Going to warp while at warp seems strange.
I know that sector space travel seems at least a little bit faster to me if I have the throttle all the way up and my power is diverted to engines.
It's not a huge difference, and I could be imagining it.
Another thing you can do that helps over the long term is to do non-combat missions that give you Diplomatic experience (like Aid The Planet and Exploration missions). As you rank up as a diplomat you get access to Transwarp destinations that can jump you directly to certain Starbases. Just like the Transwarp to ESD power that everybody gets.
Over time, you earn Bridge Officers as a reward. They can be assigned to positions on your ship and give you access to clickable powers. These are very important and get only more important over time. You can train your Bridge Officers in Earth Space Dock. As early levels, you will not have many bridge officer skill points to train them, so use them wisely.
If you have trouble in space, a few basic guidelines:
1) Running 100 weapon power and 50 shield power is usually a good choice.
2) From the Engineering Bridge Officer powers, Emergency Power to Shields is a very powerful shield buff. It gives you damage resistance, which means you take less damage. Coupled with 100 weapon power, this means you can usually kill your enemies before they can deal any significant damage back to you. At Levels 1-20, most ships can only have one Emergency Power to Shields. That means that you will be protected for about 30 seconds, and unprotected for 30 seconds (assuming you managed to max the skill). At Levels 11+ with a Cruiser or Level 21+ with any other ship, you can have Emergency Power twice. This will give you round-the-time protection. While you don't have two, just remember to have he skill ready before you enter the next combat.
3) From the Science Bridge Officer powers, Hazard Emitters is an excellent hull heal.
Do you have consoles equipped? Are you using your Bridge officer abilities during fights? These tow things I wasn't aware of when i first started and I was dying far to often. Also remember to use your arrow keys during space combat they control your shields. I run my weapons on full with shields next. and I run at 35% throttle when fighting for maneuverability. You may already know this. But It was like discovering plutonium for the first time for me.