Recommended Weapons:
Sniper Rifle - only use it from high locations for better roleplay
Silenced 9mm - only use it when no one is around to avoid suspicion
Knife - similair way to use as silenced 9mm
Locations:
Best locations to use as a hitman are unsuspicious areas, lure your target at first use any info you got, maybe he deals drugs or guns or other things that might work into your adventage.
Kidnapping:
another good way to not draw attention is to kidnap the target but when nobody is around, this is very usefull when the contracter wants the target killed in a specified way.
How to hire a hitman:
Well just calling a hitman and saying who to kill is one of the worst ways to work as a hitman, the best thing to do is to get a picture or your target's face and get his name in a role-play way. Also try to get some of the targets favoured locations in a role-play way to make it easier for the hitman
How to work out a contract decently:
To role-play as a hitman good enough make sure only to use the information gotten from the client, ask him ICly for pictures, names, locations. When he gives you a picture make sure he first will PM it on forums to use as proof later on if admins or other people see it as Deathmatch.
Then when you got all the info start the hunt, if you have been given a rply obtained phone number call your target use a cover to get him close to you in an unsuspicious area, then you can take him out anyway the client wanted it.
If you have got no phone number but you do have a name just buy a phone book at the 24/7 and find him number then to keep it role-play.
If you do not know his name but do know his face and some recommended locations, then you can try to cruise around the locations and then take him out unsuspiciously
If you only got a name and nothing else, also get a phone book and find his number.
If all the info you got is a picture then you only can drive around and if you see someone looking like the target make sure to follow him abit first see what he does and wait untill you 100% sure it is the target and that you can take him out quietly
Final, you can also use car bombs for a succesfull hit firstly its recommended you get the car of the target otherwise lure him to enter another car and blow him up, make sure you rig the car rply do not just go to the bomb shop and rig it maybe make your own roleplay situation at any garage and use /me's about how you rig the car. If the target refuses to enter the car in any way and if he is in a group try to park the car as near as possible and then press the button