Both Portals need to have the same name (case sensitive). Also, wait about 4 seconds before giving up. It takes about that long for the game to match the two portals. It will glow and make sound effects.
If you want to rename one and still need to be able to teleport, you can change the name on one end and jump into the portal really quick. Then when you appear at the other side, name that one the same as the other you just changed. That 4 seconds or whatever it is, allows you to do that. Very handy!
You will need a pair of portals for each destination. You can't have one portal that leads you to several different locations. So make a big flat area and create several portals with the glyphs facing your direction.