Most people are unaware of exactly how many types of terrain there are in the Warhammer 40k main rulebook. They seem to forget that there is a plethroa of other types besides hills, ruins, and area terrain. Let's review a couple of the lesser known ones....
Ammunition Dump: Any model within 12" of an ammunition dump can reroll to shooting to hit rolls of 1 and provides a 5+ cover save.
Comms relay: Provides a 5+ cover save and let's a player with a model within 2" inches reroll reserve rolls.
Fuel Reserve: Provides a 5+ save. After each succesful save roll a dice. On a roll of one center the large blast marker over the model making the save. On a 1 place the large blast marker over the model making the save. All models touched by the blast suffer a S3 AP- hit.... the fuel barrels exploded!
Imperial Statuary: Armies of the Imperium gain the fearless special rule while within 2". If you're behind it, you gain a 3+ cover save.
These are just a few of the terrain types that a rarely used that may spice up your game... check out pages 104-105 for more!
Most people don't seem to understand how skyfire works when it comes to shooting with fliers. Typically people like to shoot them at anything without regard whether their target is a flier or not. At the start of the shooting phase, fliers must declare if they are going to use the skyfire rule. If they start shooting without saying anything and then they require 6's to hit fliers, just like most everybody else!
If 40k wasn't truly a rock-paper-scissors kind of game, the new space marines hit the shelves and cemented it as such. Some of the most popular (and powerful) units in the game right now are broadsides, riptides, wraithknights, and wave serpents. There is one answer to all of them from the new book- centurions. Both riptides and wraithknights have the ability to kill centurions, but the same is true of centurions killing wraithknights and riptides- only they do it better. Broadsides and wave serpents lack true effectiveness vs centurions, but both die quickly to their grav cannons. So what is good at killing centurions? Orks are a great solution. The 6+ t-shirt save means they are not wounded easily and centurions are abysmal in close combat. Broadsides, riptides, and wave serpents are pretty great at wiping orc units from the board, centurions are great at wiping broadsides, riptides, and wave serpents from the board, and orcs are great at wiping centurions from the board. So what does this mean for the current meta? It means that whatever you take, somebody out there will have the means to ruin your day, so you better start hoping for favorable matchups more than ever!