The Galactic War area in Galaxy of Heroes is a fun gauntlet style mode. As your characters run through it they lose protection, their abilities' cooldowns remain in the next fight, and if a character is knocked out it cannot be used in the rest of the Galactic War until you restart it 24 hours later. This allows you to have several strategies.
- My favorite strategy which has stood the test of time, from a year ago until now, has been to create a healing/immortal team. The idea is to keep your team alive as long as possible. High damage teams will not usually survive as well as endurance teams in Galactic War. My current favorite composition for the beginning of Galactic War is Luminara Unduli or Ahsoka Tano as leader, Old Daka, Talia, and the Jedi Consular being my primary endurance team. With this team you get great healing and can stop Darth Sidious from annihilating your jedi. Focus this team on defeating enemies who prevent healing. You can out-endure anything else thrown at you unless they can one-shot you/damage you beyond your healing. As long as you can heal your team, it can last to the end. The majority of the team composition I recommended can self heal, you get stuns from Old Daka, and building this team will help you in the early game for both Light and Dark side campaigns because you level up both sides' healers. You can substitute Qui-Gon Jinn for Ahsoka, but Qui-Gon is more useful on high damage teams.
- Build multiple teams. This would require money in the early game. Eventually you will need multiple teams to complete Galactic War as you level up. The endurance team will eventually die off. You will want a damage dealing team for the last battles to pull you through. I believe a good team, which doesn't include the endurance team members, has Captain Phasma as leader with your highest damage characters (usually attackers). Having the Royal Guard on the team lets you stun (when you level his Force Pike ability) and protects your less healthy attackers and supports like Qui-Gon, Rey, First-Order Tie Pilot, Princess Leia, Biggs Darklighter, Count Dooku, Geonosian Soldier or whoever else you may have. Captain Phasma gives a chance for your attackers to attack again, and the Royal Guard protects them.
- The Retreating tactic: If you want to save a team for later and things aren't going your way you can tap the upper left corner gear symbol and select "Retreat". As long as one team member is alive, you can retreat. Retreating allows your entire team to retreat to their former state before you started the battle. Even your dead allies revive. Protection will not come back if it was lost in a previous fight. Sometimes it's better to gamble on your damage team to win quickly so you can save your endurance team for a few more easier fights. The Galactic War often puts a high quality team mid-event which is stronger than some later teams. It's weird.
- When in doubt, knock someone out. Always seek the numerical advantage. Aim for the weakest link or greatest threat to your team. It gives you more options and your enemy less. Plus, most of the characters with less health deal more damage. Try to focus fire or find ways around an enemy's tank character when possible. At higher levels Rey becomes a significant threat. I made my Rey faster rather than stronger to combat enemy attackers. Rey deals good damage already, so making her faster allows her to annihilate opponents before they can be protected. She can also get around the Royal Guard's taunt by blasting away with enough damage to one shot characters with no more protection bar.