Advice for a new player

[Soonkyu]

Well, not every 5 levels, but I went back and did them. So, if I need higher levels than 15 on my sub classes, should I gte them to 15 and Bard to 50 before I level Lancer and Pugilist past 15?

Some of the cross-class perks are worth getting as soon as possible. For example, Lancer's Blood for Blood is a great damage buff. It's honestly an essential ability. Things like Mantra, however, show you've gone the extra mile (or just leveled monk) to have all the abilities available for your particular job, but aren't necessarily going to really change your performance (unlike B4B, which will). At the end of the day, do it in the order you want to do it in. You could leave Bard at 30 while you level the other two to where they need to be, or you could get Bard to 50 before getting them. Play as you want to play. Don't get yourself into a rut by forcing yourself to level a class if you don't really feel like leveling it at that particular time.