your probably better off focusing in on delta...but i guess it depends on where you want to go more specifically....
1. Open up a chase freedom or discover card
2. Think about other ways to gain miles: Shopping portals, delta reward network, check ins etc..
3. Think about amex premier reward gold card..u might be able to get it..can transfer the points to delta
4. Just start studying deltas reward chart and partners
5. start reading the frugal travel guy blog..