Many people argue about what the best way to gain experience in Rift is but one thing is for sure, the variety of ways to gain experience in Rift make the game interesting. If there is one thing that can kill a good MMORPG it is a leveling grind that drives people away and most likely to new games.
Rift provides players with 3 basic ways of gaining experience. If done properly all three of these methods can easily be done together to maximize experience. You should by now be familiar with the in game map tool. If you haven't already taken a look at the map and know the map symbols for invasions, quests, and opening rifts you should look these up. Knowing where your closest opportunities are will help you choose the fastest path to experience regardless of if you are a Guardian or a Defiant.
The most popular experience method is by killing creatures. Killing a creature slightly more powerful than you will gain you the most experience in Rift. The best way to maximize your experience while killing creatures is to also be doing quests while your out in the killing fields.
Quests follow a path and will take you to new areas so you can always be sure to be doing higher level quests. Following the quest line is the best way to ensure you are in the right area for your level.
Rift invasions and new opening rifts are another great way to gain experience while you are out questing. When you see these events pop up on your map you can head towards the area. When you get close enough you will be asked to join the group if there are already other people there doing the event. These events will allow you to join a group quickly, kill a ton of mobs quickly, get a bonus of experience for completing the event and on top of that you can get some great items from these events.
Other Rift Leveling Guides will suggest you can use the PvP system to gain experience but I do not suggest that method for new players. Experienced players might deiced to try this system out for new toons or their existing toons if they have PvPed in other MMORPGs the system is pretty universal.
Regardless of which method you choose to level up with please make sure you continue to keep up with your gear as you level or you will start to run into problems later in the game. Rift crafting is also a good way to make money for upgrading your gear.