While I cannot claim to be the best swarmer to have played the game, I feel I know enough that I can relay some vital knowledge on the art of swarming to you. Hopefully this will prove useful in your endeavor to master every aspect of Homeworld. Let us move on to Swarming 101.
First of all I'll start by describing the 3 different types of swarms, and define their purpose. Number 1 is what most people term the bomber swarm. It is probably the most common and is hardest hitting of the 3 against resourcing. Research/build ships in this order: scouts, lcs, intys, abs, then move on to the vette classes or cap ships, depending on what you like to play. If you are successful with your strike force, you should be able to quickly kill the opposing collection and then the game is yours.
Number 2 is the defender swarm. It's purpose is to suppress someone using a bomber swarm, and it is VERY effecive in doing so if properly used. Defenders build VERY fast and are relatively inexpensive. Just remember than they are also VERY slow movers, so it takes time to get them up to the battlefront. Definitely a small map strat. Research/build: scouts, lcs, defenders, then move on to heavies and multivettes.
Third type of swarm is the vetteswarm. It's main use is against the defender swarm. This is not a particularly popular strat, since the supported vettewall offers better survivability. However, there have been some folks who like to use it because you get more firepower for that important first battle. Two SFs cost 850RU, and that equals the RU it takes to build about 3 scouts, 2 light vettes, and 2 heavies.
I subdivide my bomber swarm into three categories: the scouts, the vettes, the whole swarm. Whole swarm gets one group number, scouts within swarm get their own group number, vettes also get their own group number. If I use the defender swarm, I hotkey my defenders instead of my vettes.
Why categorize my swarm this way you ask? Because it is easier in the heat of battle to select a hotkey than it is to select a specific class of ships from your upper right hand list.
Why would I want to split my swarm? Because it allows me to attack different things independently. I can suppress the enemy vettewall with my own vettes and interceptors. I can put my scouts and defenders on their fighters. After I have gained superiority in the field, I can set the whole swarm to attack an enemy's collection, then select my scouts and/or vettes to kill any remaining enemy scouts/vettes that show up. The rest of my swarm, interceptors and bombers, can continue hitting the resource op while my vettes, scouts, and sometimes defenders kill off enemy resistance.
Hope this helps, I'll have more to add later.
Salute, Apollo(SLS)