If you want to keep players around for more than two sessions, you must find ways to get players to invest in a game beyond just imagination and hours.
Personally, I find option 5 ineffective, but it’s popular.
- Charge them money, either a full subscription amount up front for a specific number of sessions or a few dollars to pay for the next session at the end of each session.
- Have them sign an oath with consequences if they fail to attend every other week, on time.
- Send them photos of their pet being hand-fed by YOUR HAND in YOUR YARD along with a note reminding them to keep a log about the next session.
- Pay them money and make them an iron-on T-shirt with your campaign logo on it.
- Provide a meal and/or drugs (alcohol counts) with the game.
- Require that they buy gaming materials. They have to own their own dice, at minimum. Depending on the game/setting/etc your are playing, you might be able to add more things.
Alternately, host a Breakfast & Dragons experience on AirB&B. Require a six-night stay for campaigns or accept that you will only be running one-shots to completely avoid the problem of long-term player investment.