My guild just completed our first heroic this morning. So I can harken back to those days easily :wink:
First, a few basic tips:
1) For your first attempt, you need someone to really comb through rosters and devise a detailed strategy. You have to assume that things are going to be super-tight, and you don't want to waste any damage whatsoever.
2) You are likely going to need some method of communication outside of the in-game chat because the in-game chat is pretty bad for coordination.
3) People need to take time to try, try, try their attacks. They need to understand how to use airplane mode to do it. RNG can be the difference between a 2% attack and a 4% attack.
4) Mods. To do heroic, you need to have your squads optimally modded. Since most people don't have a billion great mods, this means you will have to swap mods between squads.
Onto the Phases:
Phase 1, as people have said, should be cleared by jedi squads. It took us about 25 squads, though you should plan on having backups. We had a couple under 2%, most in the 2-4% range, and a couple touching on 8%.
Phase 2, for us, is the beast. You really need a bunch of droid teams, which is not my guild's greatest strength. Even with great mods, g11 droid teams were pulling 4-5%. A lot of our droid teams were pulling significantly less damage than that for various reasons (some didn't have JE or Nebit, many weren't g11, some just didn't have the necessary mods). Overall, our droid teams pulled down about 40% of P2. We got another 10% from a couple of clone teams, another 30% from some of our rebel teams, and the remainder from a variety of teams, including the leftover jedi teams from P1.
Phase 3, if you have enough Palpatines, isn't bad. We had a variety of teams centered around him, in this order of priority: 1) Zader lead, Palp, TFP, two tanks; 2) Chirpatine; 3) Palp, TFP, three tanks; 4) Teebotine. Many of our teams pulled 4%+. The two Zader teams were 7%+. Phase 3 we breezed through quickly.
Phase was everything that was left. Because of what we had to blow through in P2, we really came down to the wire in P4.
Lessons learned:
1) In our first attempt a month ago, we didn't make it past phase 2. So we didn't know what we were going to face in phases 3 or 4. To that end, we had more teams assigned for phase 3 than just the Palpatine teams. Many of those teams would've been better used in phase 2, so we intend to reassign teams to phase 2.
2) Expect some things will go wrong. Sometimes people try their runs in airplane mode, and then forget on one run that doesn't go so well, and you lose damage you were expecting. Expect that damage will be less than you expect from the videos. It's just a really rough raid.
3) Expect it to be stressful. Several of us were tracking damage, coordinating attacks, helping with mods, helping with attack strategies and team comps, and constantly keeping an eye on the health of each phase. We were fielding questions about whether we would make it and trying to get in touch with people to make sure everyone had sent their full rosters. When it looked like we might stall out in phase 4, it started to get disheartening. When I went to sleep last night, there was about 5% left in phase 4, but we weren't sure if there was any gas left in the tank. I woke up around 4 am and checked to see what happened, was happy that it had completed, and immediately my mind started racing about whether we could do it again. I think that once we've gotten a couple more under our belts, it will be less nerve-wracking.
Overall, with a strong enough top of the guild, you can make up for some weaker members, but not necessarily a ton. Our top 15 ranged from 1.48m to 3.55m. We also had three people under 100k,and 14 members under 500k. Three people no showed. We had to line up a merc because we were concerned we weren't going to make it, with less than 10% left in the raid (shout to Team Instinct, and @TommySitt for lining up people in case we needed it!). I don't think that only 15 level 85s is going to be enough, but you can get people focusing on the right teams, you can eventually do it.