Point limits and SWC
Infinity games are usually played with between 150 and 300 points. 150 is good for unexperienced players, while 200 and 250 are popular for games that allow players to play most aspects of the game while being a bit quicker to play (and requiring less miniatures) than a full 300 points game. Additionally, the points limit also defines how many points of SWC (support weapon cost, for heavy weapons, hackers, etc.) you may spend – you get one point of SWC for each 50 points, so a full 300 point game allows for 6 SWC to be spent.
The points and SWC limit will of course have an impact on the units you can and want to take in your list. At 200 points, playing with a 100-point TAG is probably not as good an idea as in a 300 point game, where you have more room left for support and order generators.
One of the basic principles of Infinity is that every regular unit generates an order that can be spent on activating each unit (multiple times, if desired) in the same combat group. This makes it very important to have a sufficient number of units, as a cheap unit generates an order that may be used by an expensive (more powerful) unit. This is why every list should include a number of basic, cheap units (“cheerleaders”) that provide orders for the more powerful guys. These can of course serve a purpose in combat, too, as there are no “useless” units in Infinity. When playing a sectorial, these basic units are often applicable for forming a fireteam, which provides a number of bonuses (see below). So every list probably wants to include three or more of these units. They often also come with a lieutenant option, which is a good way of hiding and protecting your lieutenant.
Your list should also include some units that are powerful and can take out enemy units. These are the more expensive units that you will spend most of your orders on. Don’t forget that these will be a prime target for your opponent, so make sure that you provide them with enough support to prevent your opponent from taking them out easily on his active turn.
Infinity is objective based. Only specialists can interact with objectives, so be sure to bring a variety. Hackers, doctors, paramedics, engineers, and forward observers count as specialists, as do units with the “Special operative” characteristic. Most missions have certain bonuses for some specialist types, so be sure to take those into account when preparing your list. Some objectives (don’t forget classified objectives) also require equipment such as D-Charges that are only available on certain units. It thus never hurts to have a large number of specialists, and a few points left can often be spent to upgrade a simple trooper to a forward observer or paramedic who might come in handy.
Specialists do of course also serve the purpose one would more readily associate them with: doctors, paramedics, and engineers can heal/repair your units. Forward observers can tag units for indirect fire. Hackers are a course a sub-game of their own, being able to attack enemy units and defend and support your own.
There are a few nasty surprises that your opponent might bring to the table. Infiltrators, airborne deployment troopers, and forward observers spotting for indirect fire units have to be taken into account during setup and game play. Smoke and camouflage can be prepared for during list building. If you know in advance that your opponent will bring lots of camo, investing in Multispectral Visors and units with Sensor probably won’t hurt. Likewise, smoke can be a good way to deal with long-range total reaction units that are difficult to approach and take out otherwise. There’s usually a recipe for every threat, being prepared for the right ones is the trick.
Sectorials and fireteams
Picking a sectorial list to build your army from means not only that you’ve got different units (and availability numbers) to choose from, but also the possibility to make use of fireteams. These bring a number of benefits (activation of all troopers in a fireteam with a single order, burst and BS bonuses, among others), but also a loss of flexibility, as all troopers will have to perform the same action and drop out of the fireteam when going into suppressive fire. Nevertheless, a five-man Fireteam: Core is probably present in most Sectorial lists and a solid foundation to build on.