When to

When you play blind, you have not seen
your cards and place your bet by guessing
the strength of your hand relative to that
of other players.

By playing blind you are conserving your capital as you bet less than Seen players. You are hoping to outlast the other players by staying in the game. Play blind if have an indication that Seen players have a weak hand and are likely to fold. This is a gut feel play most of the time where luck plays a big part. You can keep risks low by placing the smallest bets possible.

You can choose to see your cards at any
time and then place a bet upon your turn.

You keep betting if you have confidence in the relative strength of your hand or hope to bluff the other players into folding.

Ask for Sideshow

If you have seen your cards, you can ask
for a sideshow after placing your bet. You
can ask for a sideshow with the player who placed the last bet. That player must not
be blind for this to be allowed. On asking
for a sideshow, you will get to see the
other player's cards.

You want to make this move when you have a high degree of confidence that your hand is better than the previous bettors.