I wont go into detail, but generally the higher the velocity you have, the slower you have to strafe and the smaller your strafes need to be, because you dont need to gain that much speed at later time in a run. So start by wide, fast strafes (fast mouse movement, not fast switching), and let them slowly get slower, but remember to not wiggle too fast when its not necessary, because it will cost a loss of speed, i always try to keep 2-3 strafes per jump. Additionally you should flick when switching strafe directions to minimize the speed loss, so basically try to always keep your strafing speed. Good strafes are not dependend on sync, but it should be atleast 80%. You can track your speed gain on good bhop servers (e.g. Sourcecode) with the !ssj/!js command. At the 6th jump a decent speed would be 570-580 on 100 tick/600 on 128 tick and a good speed would be >600 on 100tick/630-640 on 128 tick. Godlike strafers can get ~630 on 100 tick and ~670 on 128.

Apart from that, its all down to practice, it takes a lot of time to get smooth strafes. Personally, i kinda gave up on tryharding strafing, because its just way too frustating and there will always be way better strafers than you.

The strafing speed is also dependend on the sv_airacceleration value, this review is made for
values over 1000.

Technical Specifications: You should in each case have a rather large mousepad to always keep strafing, ofc a good mouse and keyboard too. Your fps should be atleast the tickrate (100 tick = 100 fps), but for smooth gameplay i recommend having >200. IMO always choose fps over graphics, so if you have low fps, go for lowest graphics settings and/or lower game resolution (for 16:9 monitors its 1280x720). Very important is your sensitivity. Good strafers almost always have a low sensitivity. I use 2400 dpi, 1.5 ingame sens, cause thats the lowest sens, where i can just move with my hand and dont have to move my whole arm, but a lot of strafers use lower sens. If you have very high sens, slowly get lower by setting down your sens by a bit or half of the old sens and get used to it. Also turn off Mouse Acceleration.

Hint: You can make your strafes look smooth by Dividing your sensitivity by 10 and multiplying the m_yaw value by 10. With 1.5 sens and the default 0.022 m_yaw value this would be sensitivity 0.15 and m_yaw 0.22. This makes you only strafe left to right not up and down, so your strafes look better. It slows you down on ladders tho and i wouldnt recommend it on maps, where you have to look at the ground/at the top^^

Heres a picture i made about strafing styles and strafe hacks: http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=729501370