I have been stack for 2 days, but have not received any reward in any coins. Simply turn on the "stacking" and wait for the result?
i m staking since day 1 (when pos activated) and no hits, on the other hand a friend is staking from day 1 as well and has 3 hits already. bad luck brah

Oh, it's depends on Luck? Bad news for me ) But anyway I will continue stack, no problem for me keep wallet open.
To make sure that your wallet is actually staking, you can go to Settings icon > Advanced Options > Console > and type in:
getwalletinfo
If "staking_active" says "true", your wallet is staking. If not, you may have to restart the wallet or toggle the Staking button off and on.
Wallet is fresh version. Balance is 13 veil