Well since the Minimum stake time is 1 hour I would say just combine all your inputs into one to create a quicker building weight, once staked I would recombine the balance again into a single input and wait for the stake, rinse & repeat.
It has been 18 hours now and the stake info icon in the lower right of the wallet( that's what I am calling it) still says estimated time for reward 1 hour.
I have received no stake rewards at all and the stake value is still at 0.00
What am I doing wrong?
You are doing nothing wrong. Your 50 coins are competing against over 570,000 other coins. With 50 coins, you can expect to get a block once every 11,000 blocks, which takes about 4 days. Don't pay attention to that statistic you get when you hover over the up arrow. It is consistently overly optimistic in many of these POW/POS clones.
Oh, I forgot, you are still also competing against POW miners to get a block too, so it may take even longer.