Newbie Seeking Advice

Eight capital ships is serious overkill.  Experience in battle is split evenly between capital ships, meaning the more you have the slower each one progresses.  This means you'll have a lot of low-level capital ships, which is inferior to a few high-level ones.  This is even more true for TEC than it is for other factions.

Capital ships have lots of selling points, but in terms of sheer damage and durability for the amount of money you pay they're significantly inferior to ordinary frigates.  High-level capital ships with good abilities can be great in combat, but at lower levels they can be ignored.  I wouldn't even regard a level 1 Kol as a serious threat, but a level 6 Kol can shred through waves of bombers with impunity.  You need to balance them out with frigate power.

Make your push early.  TEC is a rush faction that unlocks their best military units and upgrades with only three labs, and can get a wicked economy operational very fast.  Vasari is very much a slow development faction with generally weak units, but if they hit their high-level techs they become a lot more difficult to deal with. 

Easy solution is to throw down a starbase to secure your holdings.  However, as you may soon discover, the "starbase leapfrog" tactic trivializes the AI.  I find it much more rewarding to stay one step ahead of them with my fleet.  It's challenging, it requires thinking one step ahead and proactively deploying my forces, but that's the fun of it (plus it better prepares you for multiplayer where human opponents will run circles around static starbases).

Are you using any of the expansions?

Even if you have both of them i would personally play a couple games on normal sins before playing with all the expansions.

Personally I always stay with 2 cap ship (best warship and colonizer) for a good amount of time and then usally starting adding more mid game.

Thanks for the replies, I'll adjust my gameplay in terms of capital ships.  I finished the game last night, managing to build up both fleets, get them to the bottleneck system nearly simultaneously while the entire Vasari fleet was still there, get the Vasari to stay and seriously engage me, and wipe them out ... it took less than an hour for me to mop up the rest of the Vasari worlds, they couldn't build ships in any number to challenge me after that (especially since I combined plentiful broadcast centers with the high-level TEC technology that slows enemy shipbuilding in systems that I influence).

I assume when you refer to Starbases you're talking about something from the Entrenchment expansion; I don't have either expansion yet.  @MageMatthew thanks for the suggestion, I do plan on buying the expansions soon but I would like to play the vanilla game through a few times first as you suggested.

This is a typical "collapse" scenario.  The AI will often put up a rag-tag resistance for 30-40 minutes while you clean it up, but a human player would surrender at that point.  Your decisive victory at the choke point sealed the deal and it was effectively impossible to lose after that.

Good job.

Yes, starbases are the selling point of the Entrenchment expansion.  Very fun to use, but the AI has trouble dealing with them.  As I said, a good leapfrog tactic makes it too easy.

A good rule of thumb for a beginning player might be to not build more capital ships than you have fleet supply upgrades.  So if you're at the 4th fleet supply level then it might be OK to have up to 4 capital ships.

In some cases, it's okay to have 2 capital ship crew upgrades and one fleet supply upgrades.  This can be a pretty sweet opener.  Later on, though, definitely  try to work more on your fleet supply than capital crew levels.

When you are good against the AIs, it can be quite fun to gimp yourself in the same way as not leap-frogging starbases. My favorite is to get a large group of high-level caps on the field without researching any new ships and only lights on defense and early anti-militia expansion. It's surprisingly strong if you can field enough at high levels, but it is of course a very slow strategy. Next to impossible to pull off against a human player.

Thanks again for the tips and suggestions.  I've read most of SoSE wiki and played a few games through as TEC and the Advent (still haven't tried the Vasari yet).  It seems to me that the Advent KICKS BUTT; I know I'm probably playing smarter as I gain more experience, but I never seem to have a problem wiping out the TEC or the Vasari when playing Advent.

I've got another question; one thing I haven't done yet (but am about to) is play a game with active pirates.  I read the wiki info (which was slim and offered only a suggestion for a possible TEC strategy without active pirates, unless I missed an article).  Does anyone have any suggestions/advice for a somewhat-less-than-newbie for adapting my strategy with pirates roaming around?

Sidenote:  I still don't have either of the expansions, but any advice that includes the changes from them is welcome too, b/c I'll probably be getting those this weekend.

In vanilla sins, pirates wont be to difficult.  In entrenchment, they are easy. In diplomacy, they are quite hard.  Basicly... just make sure your offering 100 more credits than your enemy.  Or, use them as free exp for your cap ships. Either way you win. 

Once they get going, Advent is awesome.  Even after the illuminator bug-fix, an operational battleball is downright scary and anything short of fully-upgraded phase missiles or another battleball isn't going to have a chance of winning with even numbers.  Unfortunately, until they get going, Advent is very weak and vulnerable.  Overall they're the weakest faction since a good opponent will never let you get that "dream fleet" operational.

The biggest issue Advent has is that they have few viable openers and will almost invariably lose to a well-executed rush.  On most maps, the AI is too slow and misses this window of opportunity, so you won't really feel Advent's weakness here.  Late-game, Advent has some significant issues dealing with phase missiles and subverters, and these shut down and negate Advent's best combos.  It's not unwinnable, but Advent really only has a narrow mid-game window of opportunity to make a push against Vasari.  Again, you won't feel this as much against the AI because it doesn't use these combos very well.

Most people play with pirates off.  The feature is not well-liked by the community, though there are some people who swear by them.  Playing in vanilla or Entrenchment, don't bother spending any money on bounty.  You want to be attacked by the pirates, since this will help level up your capital ships.  In Diplomacy, pirates are much more dangerous and winning that bid (or rather, not losing it) is absolutely critical.  Sustaining multiple successive pirate raids will virtually guarantee defeat in Diplomacy unless you're a very experienced player.