Welcome to Cruisemates!
Your $10.00 pp/pd covers everyone (Room Steward, Waiters, Assistant Waiters, etc. ) except Room Service. Also, if you buy drinks (alcohol or sodas) there's a 15% tip automatically added.
The only person you need to tip in cash is the person who brings Room Service ($2.00-$5.00 depending on how much you order) or if you want to tip extra to your Room Steward or an exceptional Bar Tender, etc., at the end of your cruise.
US $$$ are the best tips. Don't try to be "interesting" by tipping in $2.00 bills or any other "weird" $ or very new bills!