Approach the cloak room on the left and talk to the guard there. You'll get an antique WWI pistol. Go to the toilet to the right of the cloak room and wait for one of the workers to enter. Be careful not to raise his suspicion or he'll leave. When he's using the toilet, sedate him and take his clothes. Put the body in the container to the right. You now have access to most parts of the level.
With the suit obtained, return to the left elevator and reclaim your Rifle Case from the top before riding all the way up to the 8th floor. The Sheikh's suite is located in the upper-left (north-west) corner of this floor (check the map for room 803 if you're unsure). With the suit and the card, obtaining access is easy.
Leave the toilet, go around the cloak room and go through the door to the left of it. Go down the stairs and past the carpenter. When you enter a bigger room, you'll see two workers having a break there. Wait until they get back to work and pick the lock in the door ahead when neither of them is watching. When you're in a long corridor, use the first door to the right. You'll eventually see a door with a golden star by it. That's not the one you want - find the one with the silver star (to the right of the golden one) and enter when the bodyguard is away. Enter the closet and wait for one of the actors to come here. It might take a while, but there's nothing you can do about it. When he enter, he'll say a few lines facing the mirror and leave for the toilet. Quickly leave the closet and swap the gun he left with the one you have in your inventory. Malevolent, isn't it?
Hitman Blood Money Casino
Go back to the closet and wait for the actor to return and take the gun. When he's out, leave the room at last and go through the door just across the corridor. Go up to the light controls. Go past the worker to the next room and place a bomb at the device shown at the screenshot below.
Now you're ready. Go back to where you left your original suit and wear it, then go to the main room of the opera and watch what happens. The actor will be shot using the gun you replaced. When everyone realizes something's not right, your second target will run down to the stage. When he's running though the audience, he'll fall down for a brief moment. When he's down, detonate the bomb. Checkmate - leave the opera and be proud.
Hitman Blood Money
A casino in Las Vegas. You are to eliminate three targets. Despite quite a lot of security, this level is fairly easy, provided you know what you're doing.
Go inside the building, to the main hall, and call the left elevator. Go up the hatch in it and wait until your first victim enters it. When the man is inside, use the fiber wire to choke him. Take his keycard and grab his suitcase. Get back to the ground floor and go to the second elevator.
Wait until Hendrik Schmutz, your second target, enters the elevator and repeat the whole process. Wear his clothes and take his keycard. Leave the Payment Briefcase and your guns in here as well - you'll get back for everything when leaving the level.
Go to the 7th Floor and enter Room 707 to take the DNA Briefcase. Now to the 8th Floor, where you have to enter Room 803. To distract the guards, set off the fire alarm (screenshot above). Once you're inside, use the phone from the table, and your final target will leave the casino area and make himself easy to assassinate.
Quickly go to the casino at the ground floor, still carrying the DNA Briefcase. Get to your target (don't go through the main floor of the casino, there are security cameras). You should manage to get there in time and kill the man when he's still alone in the staircase. If you're too late, though, just meet him in person. He'll think that you're Schmutz and call of his guard. Take the opportunity to strangle him quickly and leave the area. The exit is at the casino level (check the map). Remember to get your things from the elevator.