Where to stay
Abraham Hostel is, without a doubt, the best hostel in Israel. The rooms are spacious (for hostels), the price is low, the breakfast is great, and the common spaces are a fun way to meet people.
Here is the website. The Abraham franchise also has a tour company with safe, fun tours, both guided and self-guided, many of which leave from the hostel itself. These tours, offered at a reasonable price, may be found here.
Recommendations from former MISTI interns
Sarona Market
Sabih Frishman
Tamara for healthy smoothies
Supercoffix has lots of groceries, each thing is only 5 shekels.
Rothschild Blvd has a lot of restaurants open on Shabbat
Abulafia is a bakery open 24/7
Vitrina has the best burger I've ever had in my life
Anita has the best gelato
If you're into hip hop dance I recommend BeStreet Studio in Ramat Gan
If you're taking the bus two times a day for work, plus a few times throughout the week (I took the bus to dance), then get the 30 day Rav Kav unlimited pass for 213 shek;
At restaurants, tip is 10-15%, and you usually have to ask for the check yourself, don't expect the waiter/waitress to come to you
There's a place on King George called The Market/Kitchen for All with amazing stews and salads
If you're in Tel Aviv, go to Jaffa for a day
If you're buying fruit (or anything really) at the shuk hacarmel walk the entire length before buying because chances are you'll find cheaper prices further down.