Its all about developing a sight picture and giving yourself some space so you can make mistakes and adjust… Just like the Thunderbirds: When a new guy starts flying w/ the team the formations are very loose. As the comfort level grows the formation tightens up. When you form up on the left side of the tanker position some part of the tanker on the top right tip of the HUD’s mounting frame and work to hold the tanker in that position…develop that sight picture. Once you can hold that position consistently start moving around the tanker and start tightening up. Pick a part of the tanker and put your left or right hud frame on it. I flew helicopters in the Army, when flying a proper echelon right formation you’d position yourself so the skids on the airplane to your left created an “X”…this gave one proper clearance for horizontal & vertical spacing.
Additionally…“walk” the throttle if you can. Throttle technique is essential: make a fist like your holding the throttle…now ever so slightly “walk” the left side of your hand forward, then the right side…reverse it when throttling back…all movement in generated by the wrist. My brother flies Hornets and this is what he was taught. This forces you to use your hands rather then your entire arm when making inputs to the throttle. Develop a light touch on the controls, then learning to hover I would squeeze the cyclic so hard my left arm would start shaking…same with my legs on the pedals. One time my IP took the controls and hovered using only his index finger on the top of the cyclic. Point is if your body is locked up and tense you’ll have a much harder time with small, finely tuned inputs…think fine motor skills verses gross motor skills.
Lastly, like a few guys have already said: Practice.
1. Give yourself space
2. Develop sight pictures around the tanker
3. Learn to “walk” the throttle
4. Develop a light touch on the controls
Good luck.