First you need is a good weapon.
My Kalash full steel AK-74M replica:
This solid piece of metal is serving me now for more than two years.
The original factory wood fore grip was replaced with a kalash plum upper handguard, and a cyma black tactical lower part. The cyma part is need to be modified ti fit well into the VFC system because it is made for the LCT or Marui guns.
But after a little work it fit hard as rock.
The buttstock was replaced with a telescopic magpul type.
A custom adapter was made to install an m4 stock tube right in place of the original foldable stock.
I'm using an SSO RT-3 tactical sling, I'm very satisfied with it, I recommend.
Inside it has got an element red hop up chamber, with systema hop up rubber. Stock inner barrel, and stock gearbox, only replaced the spring guide to a guarder one. It has got factory stock 7mm ball bearings. Now its shoot around 370 FPS, and I can hit man sized targets from about 50-60 meters.