As with many maps, the lone ranger isn't going to be able to win this one. Almost all of the ways to attack this base will mean you need someone covering your back while you do it. You sure as hell can't go up the stairs to the 1st floor without someone watching the other flight of stairs, so if you want to win this level, team up with someone, and don't go it alone.
This map is fairly self contained, with the emphasis obviously placed on taking (or maintaining) control of the house, as that is where the action is going to be, with only one or two skirmishes anywhere else in the level, and with the goal being rescuing the hostages, whoever has the house will be able to either get the hostages out or keep them in there, away from the reach of the CTs. Its also a sniper paradise, as when properly positioned you can easily cover long stretches of ground, and take out enemies from afar.
Counter-Terrorist Strategy
As with almost every hostage map, the CTs only option is to charge. There are multiple entrances into the house, so sending squads off in every direction will help split the enemy team down into smaller and more manageable numbers. Of course, you can go in big groups, as I once saw 9 CTs charge in the back door and their superior numbers and firepower meant that the small 3-man squads of Ts were very easily overwhelmed.
If you want to be a sniper, then your best bet is to either stay at the spawn point and give cover fire from there, or to move inside the walls and stay in the map's corners, taking advantage of the dim lighting, and of course the bushes. For a CT squad going in the front way, the bushes can be invaluable as they can crouch and move around behind the bushes without the Ts getting a good idea of their position, so even if the Ts decide to spray the bushes with bullets, its going to be a waste of ammo on their part, as there won't be enough bullets to spray the bushes thoroughly and ensure any kills.
Once you've broken down into squads, try and regroup later once you're all inside the building, in a position such as the basement or the back room with the two chairs, and then go for the assault on the Ts upstairs, as you will need backup when trying to pull this off, or else you get shot from multiple directions when you enter the main upstairs room. Don't worry about the Ts trying to escape from the house, as only a few will ever try and meet the CTs half way through their charge, and these people end up dead most of the time, so work on getting yourself into a strong tactical position, and when you're ready and you know where the enemies are hiding, charge, close your eyes and hope for the best.
Of course, there isn't any guarantee that this will work in a public server, where you'll always have people who think they're Robocop or something charging off by themselves and getting killed, which is a disservice to the team as an extra gun can always come in handy.
Terrorist Strategy
The terrorist's strategy is a bit harder than the CTs as its always more difficult to organize a good defense than an offence. Even a slight crack in the planning can mean that CTs could spill in through a window and come up and bite your team in the ass. One possible way to avoid having to worry about this is to simply have all of your team positioned upstairs in tactical spots (balcony, ladders, hostage room, top of the stairs, etc), but then a well organized CT assault complete with grenades would quickly end the battle with the CTs winning. The better option is to divide and conquer, and send squads to each of the entrances. Have three people in the basement, one on either side of the hole in the wall, and one under the stairs to stop any surprise attacks from above if your team-mates fail. Make sure the two who are guarding the hole have grenades as well, as that will be the last thing a CT needs while he's crawling through the thin hole into the basement.
The ground floor is extremely difficult to defend, so I personally wouldn't bother wasting any people there. Attacks can come from too many directions to make it worth while, so you could be covering a window, but then someone comes in the window to your left. The only areas worth holding onto are a)The basement, so once you repel the attack through the sewers, the people down here can go up a floor and attack any CTs who may already be inside and trying to take over the top floor, plus there's a hostage in here.
b) The top floor is worth defending because there is also another hostage in here, so if this area is well defended, the CTs wont be able to take the easy way out and rescue all the hostages, they'll have to tackle your team head-on. The balcony and the windows also make this an idea spot for firing on the CTs below.
The terrorist team should generally avoid leaving the base, as you'll usually be heavily outnumbered by the attacking team, and if you spawn downstairs, get your ass either to the top floor or the basement, as a man on the ground floor is a man wasted. He's position is just far too vulnerable to justify staying there.
If you want to be a sniper, the two forward facing windows on the house and the window on the left hand side of the building are good positions. Alternatively, run outside and take up position in one of the back two corners of the level and use the shadows for cover. This can be a valuable spot as you should be able to get a few shots off before you either get killed or you're made to run away, for fear of losing your expensive sniper rifle.
