Priority for me is doing daily quests (3 x 8 AP Beginner SP, 3 x 20 AP Standard Raids) and then event quests for the rest of the day.
Daily Half Elixir, 100 Soul P, 1 x Gacha Ticket, 1 x SSR Eidolon/Weapon. Farming the higher difficulties can add 2nd Gacha Ticket, more Soul P, extra Eidolon/Weapon copies for the lb.
This really depends on how much of an upgrade the LB would be or how many materials you need for it or how good the event Eidolon/Weapon are for you. If you are new, get at least 1 Eidolon/Weapon simply for the stat boost they provide. Maybe aim for a 2nd Eidolon to lb once if you think you can get the materials together for the 2nd Eidolon.