If you are confused about how to level, let me show you some useful imformation first. Accretia have higher defense on their armor and they can find items that only Accretia can use which give a speed boost. The other races get this boost from a buff. That means you can only have a maximum of 8 buffs. So while Bellato spend 3 of those buff spots getting comparable to Accretia's armor(well slightly higher) and speed, Accretia have all 8 spots empt ......
If you are confused about how to level, let me show you some useful imformation first. Accretia have higher defense on their armor and they can find items that only Accretia can use which give a speed boost. The other races get this boost from a buff. That means you can only have a maximum of 8 buffs. So while Bellato spend 3 of those buff spots getting comparable to Accretia's armor(well slightly higher) and speed, Accretia have all 8 spots empty for more useful ones. This allows them to have more atack or cheap RF Online gold defense related buffs to become more powerful. Cora/Belalto will always at least use their dark/holy magic speed buff while Accretia move faster without that buff. So just keep the 8 buff max in mind no matter what race you pick when planning you class. You might want a class with one more useful buff than go the path of one that has 2 buffs that are better than one, but apart aren't.
You will use buffs from your normal shared skills. Maxed buffs typically last THIRTY minutes so they're almost like passive skills, except that people can remove them with magic.
Accretia also get Launchers. While these are less DPS than bows/guns at higher levels, they do do more damage with each shot. Siege kits are RF Online gold a launcher upgrade that give them more range and faster firing, however they must be deployed(takes a second or two) and once deployed you cannot move.