Well, it really depends where you are an with who you are. Ramat Gan is a subburb of Tel-Aviv and totally non-religios place, but neighboring suburb Bney-Brak is very religious place, almost like old city in Jerusalem, so do not show up there provocatively dressed.
They will not do anything bad to you, but it will be harder to communicate with them.
Look at yarmulkas on their heads - if they are black satin or silk - you are around an orthodox religious jew, basically no knees should be seen if wearing skirt and you will be fine. Knitted colored yarmulkas meen conservative - totaly normal and non-inhibited folk, but they eat kosher, observe saturday and holidays, so don't invite them to chinese restaurant or sushi place, or don't suggest to give them a ride in a car on Saturday. if guys wear nothing on their head - they are secular totally and would love to see your knees and everything else
If a girl wears long sleeve, lady covers her hair, and wears long skirt - you are among orthodox women, same rules apply. if you see the lower edge of their brests from under the T-shirt - normal Israely girls - secular.
There is no legal drinking age there and the age of consent is a pure theory, but common sence rules apply.
Guys that look dark skinned - middle eastern types - are usually sefardic - jews from Marocco, Yemen, and countries like that - they are nice people, but are a little on a conservative side about feminist movement - something you would call shauvinists.
It is about 80-85 degrees now in Ramat-Gan. April - the best time on Mediterranian shore - Ramat-gan is about 1 mile from the beach, there are some nude ones in the area. if you go to the beach - don't be surprised to see topless women on public beaches - totally OK.
Enjoy, spring in Israel is beautiful.
Oh, about guns on streets - you will see a lot of people carrying fully automatic weapons in open even without uniform - don't freak out - they are service people. almost every driver in a cab, bus, many people will walk around with handguns tucked under the belt in a belt holster - don't worry - enyone after serving in the army (and everyone serves) can get an open carry permit.