1) Place 6 and 8 for 2 units each (for me $6 units, but there is no reason that this wouldn't work with larger bets).
2) When either number hits, bring both bets down to 1 unit each.
3) For each subsequent hit, treat each number individually and follow this sequence: same bet, press1unit, same bet, press1 unit, etc... Continue until the seven shows or until you decide there is plenty of money on the table and want to collect. I usually will stop pressing at 3- 4 units per bet and leave them there. It depends on how much you are willing to risk in hope of that hot roll.
4) I have seen other place bettors who swear by taking all bets down after three or four hits. I personally believe this is nonsense, as the 7 has an equal chance of showing up on every single roll. While sitting out will often save a loss, it will sometimes result in watching the monster roll we all hope for pass us by. I have also seen variations where the bettor goes to $22 inside on the third roll. I personally don't like the high vigs on the 5 and 9 however, so I press the 6 and 8 instead.