Here's an overview of the map including callouts that are helpful to know.
Cache is a map where information wins you games. When you spread out you should gather as much information as you can. After a while you should have a rough idea of where the CTs are. Even more importantly, you know how much information they have and you've made sure they can't sneak up on you.
Freedom through mid control
If you get a kill in mid you slow down the counter-terrorists' potential quick rotation to either site. Even if you don't get a kill, but take control over mid, they need to assign at least one player to make sure you can't push anywhere without them knowing. This will also slow them down significantly.
At this point, a kill on either B or A is huge. If your B-guy wins his duel, you can support him through vent and take over the site before the counter-terrorists get a chance to react. If the A-guy gets a kill on A, you can support him from highway. You get the point: mid control means freedom and flexibility.
How do you take control over mid then? If the CTs smoke mid, you can boost a guy up to clear the area below vent or simply wait for the smoke to fade.
Either way it could be a good idea to boost a player, as long as you don't do it every round and make it predictable. That player can peek over this smoke wall while two terrorists push out from garage:
Even though mid control is a huge advantage, you don't want to go for that every round. If you notice that your enemies start to put up a greater defense in mid, you want to put more pressure on one of the sites instead.
On the next page: trying your luck at bombsites A and B.
