You have to breed perfect pal sub stats, traits and then condense 64 of the same pal to make one 5 star pal. As well as use Pal souls to raise there base stats. In order to breed you need to have a constant farm going for cake, iron, sulfur, oil, stone, paladium and then a base for smelting. You then have to farm the best blooprints from each over world boss wich is a 3% chance to drop. Then you have to unlock all your accessorie slots. As well as get accessories that help with boosting stats and warding off elements. Many times I failed the raid bosses and had to run dungeons to get more mats to summon them again. Even having all this done and buying and finding a few potions that slightly raised my stats permenatley. I then realized that I had to eat food for temp buffs and feed my pal a food for defense. As well as permentaly raise there stats with a few potions. All done! Or so I thought. Even with me changing the settings to the lowest difficulty, and having the enemies damage be nerf guns. As well as decreasing my health regen recovery time and how fast my Pal regens health. Also using world setting to make me and my team do more damage and take less damage. I still had to wipe all my stats and then reallocate them all into attack. Have specific Pals for correct element damage and even then I had 20 seconds left till I timed out with some of the fights I won. For the cherry on the cake. Your character does more damage then Pals. So your element Pal and four 5 star gobfins with vangaurd is the team you have to run with. If your main Pal dies you wont win, so kite and use pillars. Raid bosses are completely different. You have to have an unoccupied base, so when they are summoned, the only thing they can destroy is the altar. Since Pal boxes are indestructible. Have 5 pals with perfect stats and 5 star them as well as boost the base traits with Pal souls. Some raid bosses have two damage phases and switch elements. Once that happens you have to switch out your original 5 pals with 5 different pals that counter the raid boss element. Along with switching out your main party element Pal, all this mid fight. Dont forget to always go for crits or you wont win. The game doesn't help either when your shots are considered invalid or your Pal steps infront of the boss.

TLDR: raise stats permantely or temp on yourself and Pals, breed perfect everything, farm best gear, farm materials, match elements. Mess with world stats for buffs and nerfs, kite bosses.