The Bahai Gardens
The main attraction in Haifa is the Bahai gardens. Hours may be found here. It is recommended you go from 9:00-12:00, because that's when you will be able to access the inner gardens. There are three levels to the gardens, and which level(s) you may enter varies.
When visiting, dress modestly-- cover shoulders and knees, regardless of gender. The Bahai gardens are a holy site; visitors should be respectful.
There should be a English tour daily at 12:00.
Downtown
Downtown (by the port), you will find a cluster of restaurants and bars. There is also a Cofix Bar, which combines cheap iced cafe with cheap beer and liquor.
Dado Beach
Located right outside the Hof HaCarmel bus and train station, Dado is Haifa's best beach. Much less crowded than Tel Aviv, there are spacious public locker rooms every couple hundred yards. There are also many cafes and ice cream stands right on the beach. Camel is a good but pricey restaurant; drinks are very good but will run you 50 shekels.
There are lifeguard stands along the beach. When you go to Dado, look to see where/if people are swimming. If there is a black flag, do not swim there. Red flags are usually lined up to give you an idea of the zone you may swim in. How strictly this is enforced depends on the tides, currents, and lifeguards.
Jellyfish season begins early July. In 2018, Dado was swimmable throughout August.
Pride
In July, Haifa has a Pride parade. While it isn't as large as the one in Tel Aviv, it is a fun thing to see on a Friday morning. Many families attend. The best place to watch is downtown; the route runs straight through there.