Just be sure to always have a Plan B, or Plan C!  A wise player will EXPECT you to counter in such ways as mentioned above; expect Seeking Dispels, Dispels, Sleep, Dissolve, and any other collection of defensively offensive spells as a means to ensure their flying army stay dominant in the arena.

I have been theory-crafting a spellbook for my Beastmaster (have yet to be able to test it out in an actual game, but that will change this weekend).  I call it the "Wolf Pack" because it implements Redclaw and Timber Wolves as the main source of damage, though I still include heavy-hitters/tanks such as the Grizzly and Mountain Gorilla.

I agree with what has been said above, but make sure to not focus ONLY on creatures.  It's important to still leave yourself plenty of points for those enchantments you need to counter anything an enemy might have in their spell book.  With the "Wolf Pack" spell book, I lack a lot of flying creatures so I need to utilize Maim Wings and Eagle Wings to be able to fight any flying creatures my enemy might use against my primarily ground-based forces.

I'd like to include my spell book composition below not only for reference for your original question, but also to present it for constructive criticism for those who have had the opportunity to play a Beastmaster in a live 1-on-1 match of Mage Wars.

Equipment:
Bearskin
Elemental Cloak
Enchanter's Ring
Gauntlets of Strength
Mage Wand (my intent is to bind Minor Heal, Perfect Strike, or Rouse the Beast - whichever suits the situation)
Moonglow Amulet
Regrowth Belt
Ring of Beasts
Staff of Beasts

Attack:
Geyser

Creature:
Bitterwood Fox (x3)
Emerald Tegu (x2)
Fellalla, Pixie Familiar
Feral Bobcat (x2)
Mountain Gorilla
Redclaw, Alpha Male
Steelclaw Grizzly
Thunderift Falcon
Timber Wolf (x3)

Conjuration:
Animal Kinship
Lair
Mana Flower (x2)
Mohktari, Great Tree of Life
Rajan's Fury
Tanglevine (x2)
Tooth & Nail
Wall of Thorns (x2)

Enchantment:
Bear Strength (x2)
Block
Bull Endurance
Cheetah Speed (x2)
Cobra Reflexes (x2)
Eagle Wings
Maim Wings (x2)
Marked for Death
Mongoose Agility (x2)
Regrowth (x2)
Retaliate
Rhino Hide (x2)
Turn to Stone
Teleport Trap

Incantation:
Banish
Battle Fury
Call of the Wild
Dissolve
Minor Heal (x2)
Perfect Strike
Piercing Strike (x2)
Rouse the Beast (x2)

Again, the intent of this spellbook is to be well-rounded in a variety of situations, but also to specialize in using the wolves for my main fighting force.  (I've been toying around with the idea of removing a few zone-exclusive conjurations (like Tooth & Nail and Mohktari) to make room for Dispels and Purge Magics.  My logic, though, is that with the amount of creatures I have at my disposal and their attack power, I will be killing enemies faster than they will be killing my forces should the enemy have build a spellbook that focuses on damage over time (DoT) curses.

The traits do stack, from my understanding, but only if the cards have unique names.

For instance, you can't have two Obelisk's effecting the same creature.  There are always exceptions to rules like this, so be sure to read each card thoroughly to understand how it interacts (zone exclusives, epic, legendary, etc.)