Exping..

There are several ways to get Vitality back. Best one is to hunt where mobs drop herbs so that you can get Vitality herbs. There are also the Pailakas (lvl 37, lvl 61 and lvl 73) that will refill totally your Vitality upon completion (as well as give you several lvls). You can also get revita-pops with event coints (Event Apigas), at the eevent NPC in Giran.
Of course there is also the slow refilling when the character doesnt hunt/is off, or the buff you can get at the NPC buffer with some Golden Apigas from donation.

What class are you playing?  Different spots are better for different classes.

Give the upper part of Blazing Swamp a try (don't forget the red gem quest if you do) or if you feel like that is to easy try Shrine of Loyalty.  Plenty of herbs in both those spots.