experience designing cube

You want to create decks for archetypes that are in your cube and build your cube around those archetypes. Your first inclination is to grab an even split of cards from each color and work your way through by mana costs. While this approach can work, it doesn't create exciting boosters to open.

What you want to do is decide which archetypes are going to be the focus. For example, let's add Reanimator. You'll build a "perfect" version of the deck, as though a person has 20~30 picks that fit into Reanimator. Add this perfect deck to the cube, making cuts as needed to make room. Then you'll want another archetype that overlaps with Reanimator, like Ramp. Except this time, you'll include cards from Reanimator for the ideal picks/perfect deck (such as Eldrazi or Woodfall Primus).

Violiñá! You now have two options for your players to fight over. You'll repeat this process with your other archetypes, creating a sort of "ring species" of decks. You'll want around ten archetypes, with leftover spots used on cube staples (Sol Ring, Swords to Plowshares, Demonic Tutor, Wrath of God, Llanowar Elves, Force of Will, etc.) or your whacky/pet/Unglued cards.

The goal is to create tension during the draft portion. It makes opening cards that aren't yours or new fun because players can think about what cards they need to build their deck. Once you get a few drafts under your belt, it will be time to add and remove cards. You'll want to cut cards that always get picked last and you as a drafter see commonly passed around. Something like Mana Crypt won't make it far before someone takes it, so you know if you're seeing Wood Elemental every draft it's probably time to cut it.

Lastly, Louis Scott-Vargas (LSV) has a YouTube channel where he drafts on a daily basis. Most of the time, it's teamed Vintage Cube. That's a great way to see how a high power cube functions and he gives excellent commentary on each card in the cube, whether he's playing the official MODO cube or his own.