The downside to JDate is that it is a membership-based site, and the membership runs at -40 per month (depending on whether you purchase a shorter or longer period of months).You can create a profile on JDate for free, but you cannot message anyone until you get a paid membership.Sometimes this can be after a shul service (a casual young professionals area) or an event on its own at a club or bar.
To find Jewish social events, first make sure you are part of or in some way connected to Jewish groups (sounds obvious but some people forget this step).
Examples of Jewish groups are Aish Hatorah (Orthodox group), Moishe House (generally Conservative, but Jews of all backgrounds welcome) and Hillel (Jewish college-level group).
Israeli girls are more direct and straightforward than other Jewish girls (and maybe a little more mature and grounded).
Other Jewish girls may hide what they are thinking a bit more.
If you live in Israel you can find and meet Jewish girls pretty much anywhere.
If you live outside Israel you have to search a lot more as Jews are obviously much less common.
If you don’t know any Jewish groups in your area, you either are not involved at all in Judaism (and need to get involved) or there are basically no other Jews in your area (in this case you should move to where there are Jews or do the 1st option above – online dating).
Sometimes Jewish groups also organize specific Jewish singles events.
Before I start, let me first tell you that the advice you’re gonna get on this page is from an actual Jewish guy who has dated numerous Jewish girls (not too many but enough to have something to say ;-D).