I don't think running faucet is still profitable because most of the faucet are subject to bot attack as well as there is no any good bitcoin adnetwork that pays well.
However, there are few things you should consider on making your faucet;
1. Don't put too high reward for small time difference, try to find suitable number of satoshi that will be profitable for both you and your users.
2. Try not to have multiple ads from same adnetwork all over your faucet, use multiple adnetwork.
3. Try to submit your faucet in multiple faucet rotators to get extra/free traffic.
4. Have good referral commission but not make it too high that can attract bot attacks.
5. Try to use good, short domain and good hosting for your faucet.
6. Last but not the least, try to actively promote your faucet in multiple places and keep good track of your profit and expenditure.
Thank you