Okay, playing as Advent in the current patch is like taking a handicap in multiplayer. Against the AI it's not such a big deal, against a human player every small disadvantage counts. You can get a lot of respect points by winning as Advent these days, but if you're struggling just to compete it's probably a bad idea and you should change factions at least until the next patch.
Colonization speed is definitely a huge issue, and I wrote a thread about this a while back discussing some strategies you can employ:
https://forums.sinsofasolarempire.com/363623
I'm not going to repeat much of was said in that thread, but the key is to keep moving at a constant and steady pace, avoiding delays as possible.
As far as militia goes, you need to pay attention to Javelis LRM and Kodiak Heavy Cruisers most of all. If the militia doesn't have these unit types, it's going to be a pushover no matter how many units it has. If it has plenty of these types, you probably want to avoid that militia until you have a big fleet that can mince it proper. You also want to pay attention to the Krosov Siege Frigates. If you kill them, you're free to colonize the planet, so if there's only one Krosov, you can quickly kill it, colonize the planet, then build turrets and repair platforms to help finish the job.
and i am not sure when to start buying less combat ships and more support ships (subjugators, iconus guardians, rapture, revelation)
I'd avoid subjugators in general. Too many labs, too much research cost, too little performance. The others all have their places in moderation. You need a strong fleet first. The Iconus is a powerful support cruiser, but you need three shield techs as a prerequisite to research it plus it's not very effective unless you have a progenitor. That's a big up front implementation cost so you probably want to wait until you've filled at least your first two fleet upgrades with combat units. Advent needs to bring out a larger variety to succeed, but if you have too little firepower it won't do you any good.
and how good are the basic defense platforms, are they worth buying when your fleet is too far away to defend
They're too vulnerable to bombers, and too vulnerable to long range frigates, which means that unless you back them up with frigate power, they're useless. They can supplement your frigates if you want to cover a flank with fewer defenders, but they won't do jack on their own.
also, is it possible to jump to a location where an event has occurred? i get auto-messages saying that me or my allies have encountered enemies at a certain planet but its frustrating to look for that planet on the map.
Every planet you have vision of has coloured "pips" that tell you how many units are there. Look for planets with large numbers of both friendly and enemy pips, and that's your answer.
