1. Ancient Coin - Highest gold, passive playstyle, requires no work but picking up in drop radius.
2. Spellthief's Edge - Requires hitting enemy champion to proc gold, no hit, no gold. Best for ranged, aggressive style of play on the bot.
3. Relic Shield - Best for melee support with aggressive gameplay, otherwise, an ancient coin is better. The only exception is if you want additional sustain to help heal you and your ally, for example, if you are playing a non-healing, melee character like Pyke.

Macro is the biggest problem with low elo players. (bronze - gold)

Macro involves map pressure and objective management. Watching the clock for objective spawns and ensuring your team moves towards completing those objectives.

Two questions:
1) What is the easiest objective for YOUR TEAM to take?
2) What is the easiest objective for YOUR ENEMY to take?

Buy Control Wards - 6 controls wards per 30 minutes.