Monomi said:
is it worth still detail scanning system when they have all ready bean discovered?
Yes! Definitely! It takes a little practice, but you get into a rhythm with each jump into a new system.
Jump in, aim at the central star, slow down when the fuel scoop kicks in, hold in the Advanced Discovery Scanner (BWONG!), check the System Map for anything that might be interesting.
By the time you've checked the System Map, your fuel scooping should be done or almost done. The ones to watch out for are Earth-like worlds (blue & green), water worlds (mostly blue), high metal content worlds (various colours, but more than just a rock).
If they're at the right distance from the star, they might be Candidates for Terraforming, and that increases the amount paid out for the scan data when you sell it.
The only ones to avoid altogether are asteroid belts. They are literally worthless.
Monomi said:
Do i still scan discovered areas or try to find my own undiscovered areas?
Yes, scan previously discovered systems because while you might not get the first discovery bonus (+50%), you still get Cr for each star, planet and moon you scan.
The main advice I'd personally add is to get a fuel scoop in your largest slot, but not necessarily A rated. That's just paying lots of money for little extra. In your case, I would suggest a 4B Fuel Scoop.
An A rated Power Plant copes with heat better. You can get by with a 2A Power Plant which is lighter, manages heat and still provides enough power for your modules.
http://www.edshipyard.com/#/L=70i,mpT5QG5QG0Wg,2-4s6u7_5K5K5K8I,4-40MM7Q42jw2UI