Some of these were very hard won... don't learn them the way I did.
1) When clicking to join an acs attack it will auto fill the location but not the "planet, moon" field. You have to correct this yourself (78million res mistake)
2) Whatever time is on the attack it can never be reduced... ie, if someone acs's on and slows the attack, you will not speed up the attack by having them recall. So either everyone recall or no one does.
3) You can not see other peoples fleets unless you can lanx... so you better trust your friends. If you would not trust them with your fleet, don't acs with them! There is always the last second recall also...
4) Unless everyone involved is pro, your timing will be destroyed. Its called experience (or lack thereof).