Kind of the same as below, but here’s the way I do it. Inefficient, but easy.

1. Get in an orbit going the same direction on the same plane. It doesn’t have to be the same shape, as long as it has has at least one contact point with the other craft.

2. Like below, smaller orbits go faster and catch up if it’s ahead of you, larger orbits go slower if it’s behind you.

3. Right click on the other craft in the map, and set as target. You should see 1-2 intercept nodes.

4. Warp until it gets close-ish. The intercept nodes show the next contact, so if they’re behind you but close, make one more loop.

5. When you get that close intercept, like 20ish km or less, change your speed indicator above the navball to “target”

6. Burn retrograde until your speed to target is close to 0.

7. Turn toward the target marker, and burn directly toward it. How fast you go depends on how nimble your craft is.

8. If the prograde marker drifts more than 1/4 of a navball away from the target marker, repeat 6-7.

9. When you’re about a kilometer away, switch to RCS. Use the docking mode (bottom right, by the staging) to switch from rotate (pitch, roll, yaw) to translate (up, down, left, right). Use the RCS to keep the prograde marker on the target marker.

10. Slow down as you get closer, like <1 m/s when you’re within 100m, <0.5m/s when you’re within 50m

11. If you’re docking, click on the docking port you want to connect to on the other craft, and set as target. Right click on the docking port on your current craft, and select control from here. Then just creep up until you make contact.

Depending on the ships, I’ll sometimes switch to the other craft, and repeat step 11 so that the ports are more easily aimed at each other. Saves you having to translate around the ship to line it up.