"In SP or skirmish games, never forget your salvage corvettes. On the main forums, there are the "great ones" who can easily get fleets of over 2000 ships this way, but you don't need to be that dedicated. A few properly supported (or cloaked) salvage corvettes can save you RUs if nothing else, grab the big ships (usually from below) and you don't have to pay for them. Heavy Cruisers fall much quicker to salvaging than to firepower. Just want to kill everything? Go ahead and send some in anyway, if even one latches onto a frigate, or two or three onto a heavier ship, it will impede their movement and make them sitting ducks for your fire. Then heal the corvettes and do it again. MP is a different ballgame of course... " - Nevaron

"Get The Most Bang for Your Buck:

Buy those units with the most flexibility and endurance. Resources are always limited, but units which can survive combat are better than cheap ones which go boom quickly. Seem obvious?

Light Corvettes, even Heavy Corvettes are too small to take much damage, and yet not maneuverable to evade hits. Ignore them unless you are desperate for defense and cannot afford anything else.

Scouts are good for when you are budgeting, but take interceptors over them whenever you can afford it.

If you can buy 4 Strike Frigates or a Destroyer, get the Destroyer. It is easy to control (especially with larger fleets) and easier to repair.

Support frigates are one of the most useful units in the game. They can refuel fighters, they have decent speed, they can repair anything, and they can even fight a bit.

PROTECT YOUR INVESTMENT

Build repair units (particularly Support Frigates) and put them on permanent duty on Support mode for your capital ships. Put the SF into a group, then task them to support another group. They will automatically repair units when damaged. If a particular unit is getting pounded, set the whole group to repair it. They will trail behind and are often ignored. They can also support any escorting fighters.

Conserve your fighters. They are not cheap. Withdraw from a fight when you are low on fuel, damaged or outmatched unless doing so will cause more damage. Refuel them whenever there is nothing happening." - Captain Wrath