What was the best way to do it?
What I've found has worked is to take an image or idea that causes piti and friendliness. Sustaining that image/thought over time and practice will build the first jhana. For me, once that becomes well sustained, then the associated sensations quickly suffuse into the suffusive, vibrations of piti, leaving behind the sustained word or image used in first jhana. Metta gave piti (2nd jhana) an outgoing-sensation (like dissolution but with a massive energy feeling as opposed to dissolution's lack of boundary and gentle, out-flowing-sand quality). As the piti dissipates into comfort then into equanimity, the metta quality contacts (or rides on like a board on surf) an increasingly reduced feeling of energy (from 1st piti to 4th equanimity) and becomes more like very whole receptivity and uniformly vibrant, like being magnetized to environment and without any gradient flow, just magnetized. I have only experienced fourth jhana a handful of times and each time it seemed neutral but also deeply engaged-- as if fourth jhana -- as if this pure equanimity --- in a human being
is metta. (Keep in mind I have very limited experience to draw from.)
If you can, consider doing this in a place around people that wouldn't be too weird: natural places where people just sit around and look quiet and mildly pleasant are park benches and/or a meditation hall during a discussion period after zazen for example.
There are lots of different circumstances to field this practice, many well beyond my skillset. Each person is different. It would be interesting to learn what you bring to this study and to the forum aslo!
Edit: re-reading this, I can see how a technical effort like this seems totally removed from a practical outcome, but it is practical. Like learning to ride a bike, a person (such as me) needs some practice before riding to the store or going down a trail.