Post your best strategies
Base Ship: Upgrade move 4 or 5 times as you focus on picking up scrap, then passive scrap, don't worry about shield. Keep picking up scrap, but help fight the odd ship that you can take. Use your shield to run away if you can't win (you're faster). Once you have enough to upgrade, keep picking up scrap until you get 1,500 (max), then upgrade with a reserve to get you started.
Suicide Squad:
Use the Utility - Engi path, because they both get passive scrap, making upgrades fastest. Max your movement first so you can pick up scrap. Max abilities; then the fun starts.
Suicide Attack: Get about 2,000 scrap, then head for the enemy base, trying to avoid enemies. If there's an assault on the enemy base, tag along. Spam the suicide drone button when you're right at the base. A good attack with not much enemy opposing you can take nearly 1,000 damage.
Base Defense: Are you getting pummeled? The Suicide Squad is an excellend defender, especially against sneak attacks. Hang out at your base, picking up scrap nearby. Keep a few suicide drones on so if a stealth pops up you can take it out immediately. If you have a good store of scrap, you can deliver an enormous payload in a short period of time if there's an enemy raid.
DOD / Alert:
For the Alert, use the Sniper route, as it's sniper shot can be pretty useful while you're upgrading. For the DOD, you'll have to use MOD, but don't waste scrap buying turrets. They won't do much good yet. Fully upgrade, starting with movement and passive scrap to make it faster.
Turret Island: Make sure you have a good stock of scrap. Start building turrets about halfway between the bases, in the path of the enemy base. Place them all in the same spot, or in a slight arc to protect yourself. Keep pumping them out every 5 secons. They have a limited lifetime, so if you start too far back, you'll just be wasting your scrap. By the time anyone realizes what you've done, you'll have an army of turrets. Ships will approach to take it out and be pulverized. When the enemy base rolls around, keep pumping out turrets and fire on ships and the base. This is probably the most powerful individual attack strategy. If another turret maker sees what you're doing, he'll probably join you, making it even more powerful. Other ships can use your turret base to launch a devastating base attack. Make sure to give them a big smile, as the base floats by :D
The Doctor:
The only path to the doctor is Support - Healer. The Doctor's speed and ability to heal makes it a good ship for suicide runs if the enemy base is not guarded. It also works well to distract individual ships that are grouped, and be able to get away unharmed. Unfortunately, time travel is not equipped.
Little Buddy Strategy: Find a big strong buddy, and hang out just behind. A group of buddies is better. Heal them as needed, and fire from safety. If it looks like it's going bad for your buddy, you can always jet off and find a new buddy, or meet up with him on his way back to the front line. A single Bully with a couple Doctor buddies can be nearly unstoppable.
Mechanic
The Utility-MOD path will give you passive scrap and make upgrading faster, although MOD is pretty useless, so you can also go Support-Healer.
Base Mechanic: If the other team is outdoing your team in base damage, healing your base is as good as attacking theirs, and much safer. Run around picking up scrap, then unload repair bots on your base. The amount of healing a Mechanic can maintain throughout a game could easily make them your team's MVP.
Turret Island Support: If your base isn't in need of repair, use the same tactic on a turret island, if you can find one. A Mechanic is an ideal partner for anyone building a Turret Island, and is probably the most effective use you can put your repair pods to.