A lot of it comes down to dealing with strong, late game monsters. Basic strategies are:
1. Have multiple defenses with damage that scales off those defenses.
2. Have massive speed, killing monsters before they can attack.
3. Have counter attack, combined with quick healing.
4. Hide behind summons while you scale up power.
Plan on how to quickly build up killing power. Meditate is good, but it's hard to build it up fast without hiding behind summons and/or slowing enemies (freeze, paralyze). Charge is great, and you can build up speed with killing power. In Flame works well with melee builds, and synergizes with several equip pieces. Repulsion can build power and potentially all three defenses.
Check my builds.