I'm of the believe it's better to spend a charge immediately entering lane, so the Relic Shield CD can start counting up to maximize the item's gold potential. The issue with this approach is the ADC and/or yourself misses out on the HP gain, since you'll likely both be at full health.
What's the correct Relic Shield approach?
I personally use up both charges immediately. But I usually play Leona and like pushing for that lvl 2 advantage. To really not be missing out on any of the gold potential though, you just need not hold max stacks. In essence you can only get one cs of gold ever time a charge comes up regardless of how many stacks you've saved up if you do it perfectly. So holding stacks of it just makes it more forgiving and strategic in when you actually proc it, such as saving a charge to heal your adc.
TL;DR: Just get the first melee minion and then save stacks for heals/cannon minions. You only lose gold when you are sitting at max stacks.
I'll proc my targons once, then I'll save some for the cannon minion or when I need to heal my ADC.
If you use your targon stacks on the first 2 minions, you'll get your next charge just in time for the cannon minion. But yeah it might be wise to only use one when you first come to lane in case you need the sustain.
Not sure what you're trying to ask here. Just last-hit low health minions near your ADC for more gold gain; for efficiency, save it for cannon minions and melee minions.
Walk into lane, immediately trade, then execute a minion
PROBLEM SOLVED
Get the first melee minion, save the second proc for the upcoming cannon minion. If I remember right a cannon minion comes every other wave. If your ADC needs health ASAP you'll be happy you saved a proc for a cannon minion instead of wasting it.
The heal is nice to have but it's the gold I'd personally be prioritizing in this case. Unless maybe you're in a lane where you expect to see a ton of harass coming out at level 1, then I'd consider holding off for that extra few seconds.
