If you want the “Skill” level to reach 99, it should be easy enough. If you can, just make lots of familiars for your discovered marks and make sure you always use them on skills and/or combat, since each creation AND use will net you some summoning points for the skill levels.
Constantly using familiars will get you done in no time. For “Mark” levels, you also need to keep using the familiars since they drop at the mercy of the RNG Gods, so it’s a grind.
Now the “Mastery” are a different beast, since they only level from making them, and not from using them (as far as I know).