The stronghold's first and second-level creatures have good attack but very weak defense and hit points. They aren't durable and so need to get their attacks off quickly. The goblin is actually among one of the weakest of first-level troops. The wolf rider has the best attack and speed of the second-level troops, but dies quickly. The wolf raider is a little better due to its two attacks and better speed, but it doesn't improve in durability. Don't count on your first two level troops to survive many skirmishes.
The orc is now a third-level creature, and it is a poor ranged unit, weaker than the elf and even the lower-level marksmen and magogs. You'll have to make due until the powerful sixth-level cyclops is available. In fact, from levels four through seven, the stronghold boasts some powerful creatures. The ogre is very durable and strong, and the ogre magi even more so. The roc is a cheap level five troop that can be acquired quickly and is strong and fast. The upgraded version, the thunderbird, is faster still and has a chance to call a lightning bolt on the thunderbird's target. The cyclops is a strong ranged attacker, second only to the titan, although it suffers the ranged unit's penalty when engaged in close combat. The cyclops can also be used during castle sieges to break down castle walls much like your catapult (cyclops kings get two attacks). Try using multiple stacks of cyclopes to bring down enemy castles quickly. The seventh-level creature, the behemoth, is a strong brute, but is even better when upgraded, as its special ability can set up the target for powerful follow ups by the cyclops' ranged attacks and the quick thunderbirds. Compared to other seventh-level creatures, the behemoth comes out on the losing end, but you can acquire it faster than any other town's seventh-level creature.
You should strive to upgrade your rocs and wolf riders first, because they have the most significant offensive upgrades. Cyclopes also gain significant advantages from upgrading, but it's usually hard to acquire them early on because of the high crystal requirements. Then upgrade ogres and orcs. In general, the stronghold creatures are pretty slow, which is another reason to upgrade all your troops as quickly as possible.
Good mid to late level troops
Two ranged attackers (one mid and one late)
Cyclops is a great ranged unit
Can escape from towns under siege
Can jump to behemoths in three turns
Weak low level troops
No castle moat
Very weak in magic
No good early ranged attacker
Mid level troops are slow
Only one flying unit
Need lots of crystal, wood, and ore
Thanks to The Nether Gods team for the contents of this page!