Okay - so this might sound like it contradicts nearly EVERYTHING on this post, but you can try it, and it worked for me (at least for now)
1. Get 757s if available. You can use them on nearly every type of route. Use 1 first class seat to every 7 business class seats, and 3-4 first class seats for a 757 should do. Fill up first class and business class, and when checking economy class, do 10 less seats than max capacity. This gives you good reputation.
2. Join the largest alliance possible. If there are two alliances that are very close, take a look at the two and choose the one with the most airlines on top 20.
3. Small airports. Google maps. Wikipedia.
4. SPAM your 757s on transcontinental routes from small airports in large cities.
5. Add "feeder" flights that are about 1-2 hours from your "main" airports (i.e. if you do Burbank-Hollywood > Charlotte, do flights from Burbank to El Paso and Charlotte to Durham or Savannah.)
6. IFE and IFS: as generous as you can be IF AND ONLY IF YOU ARE JOINING A "legacy" GAME. YOU WILL NEVER CATCH UP TO AN AIRLINE WORTH BILLIONS/TRILLIONS OF DOLLARS, BUT REPUTATION WILL ALLOW YOU TO COMPETE ON A DIFFERENT PLAYING FIELD. Disregard if you are in a "new" world.
7. Set up 3 "hubs" (but don't make them hubs) on the East coast (small airports near large cities). Set up 3 "hubs" on the West Coast (small airports). Connect them with transcontinental flights.
8. Once you start hitting 50M DOP or so, you can start being more aggressive. Don't forget that larger airlines are making 500M+ DOP, so you cannot be too aggressive.
9. Little tip regarding A330-300 and A340-300: A330-300 is more expensive, burns more fuel, has less range, but the same seating and speed as the A340-300. A340-300 has a longer turnaround time (75 v.s. 90 minutes).