Your attacking order is important. The blue meter under each character's health bar indicates how much time remains until they attack. When full, that character will attack. When a battle or new round starts, target the the enemy that will shoot last. This gives you a chance to take them out before they can become active. Kill a single enemy instead of spreading out your damage. This will reduce the damage you receive. It is usually a good idea to take the weaker enemies first.
Crystals
Crystals are the game's premium currency. You can spend them to buy Chromium Data Cards to unlock more characters. They also can be used to get more energy, reset the time counters, etc. Log in daily for a month to collect the daily reward to save crystals. Complete the daily missions to earn crystals. Complete campaign under the hard difficulty setting. The normal difficulty setting has crystals as a reward upon first time completion. Earn achievements to earn crystals after completing some of them. Get a high enough rank in the Squad Arena to earn a daily reward of crystals.
Heroes
Collect Data Cards to increase the chance of getting more characters or shards. They can be obtained by completing special events. You can get a free Bronzium Data Card every ten minutes. You can also spend Ally Points to get them. You will rarely get heroes from them. Log in daily for a month to collect the daily reward. A new hero will be on the rewards list each month, and can be claimed with shards. Replay hard battles to collect shards that can be spent on heroes. You can choose which character you wish to unlock. You can also get shards after completing normal battles for the first time. Earn the achievements to unlock Darth Vader. Spend Crystals on the Chromium Data Card Bundle to get Heroes and Shards. Purchase Shipments for a chance to find character shards.
Skills
Each hero has different skill actions they can perform during their turn. Learn your heroes' skills and use them when they are most effective. Take note of the cooldown required to use those skills multiple times and time them appropriately.
Training
Keep training your characters in order to make them useful in new missions. upgrade your best characters first, then replace the less powerful characters as new heroes become available.
Various Achievements
Complete the following tasks to unlock the achievements.
Achievement
How to unlock
Points
Arena Fight
Defeat hundred opponents in the Arena.
1000
Days of Spring
Open 12 Days of Spring Data Card packs to collect 24 items.
1000
Earner
Earn 1,000,000 total credits.
1000
Gather Your Strength
Open ten total packs.
1000
Guild Contributor
Contribute 10000 Guild Bank Currency.
1000
Guild Earner
Earn 5000 total Guild Currency.
1000
Guild Raider
Finish five Raids.
1000
Mod Enhancer
Acquire one Mod.
1000
Mod Master
Acquire six Mods.
1000
The Force is Strong In You
Complete the first training mission.
1000
The Light Side Path
Complete Light Side Campaign Stage 1.
1000
Various General Tips
Familiarize with each character skills and their cooldown time, which could give you a good clue as when to use a particular skill.
Gather Data Cards by completing special events to unlock characters.
The more events and missions you play across the various difficulty settings, the better your chance of building a solid roster.
Watch the blue meters positioned under a given character's health bar and when that bar fills, the character gets to attack.
Target one enemy at a time, so that you can more quickly get rid of sources of potential damage.
Attacking...