Postcard entries cost less than envelope entries, which means you get more entries for your dollar. Use basic supplies. Don't go overboard by buying expensive decorated supplies. If you think that decorated entries might be lucky, try decorating them yourself by using markers, stickers, stamps, and so forth. You don't need to buy multiple sweepstakes newsletters.
Many newsletters carry the same sweepstakes, just at different times.
Enter the sweepstakes with prizes that you need. Sure, that spa vacation might be nice, but if your car is dying, you might want to use an extra entry or two to win a new vehicle. You don't need any special organizers for sweepstaking. A nice sturdy box holds all the supplies nicely. Cut up cereal boxes to make dividers to separate your supplies.