Use high levelled accounts to trade. Both when receiving and trading off gold.
Avoid common RWT hotspots (lumbridge, GE)
Put items in the trade screen along with coins. Tell your customers to also add random items in the trade screen.
Use platinum tokens.
Stage risk fights in PvP worlds.
Drop trading.
Duel arena.
Trade using high gp-value items, Scythe,T-bow, Inquisitor sets, etc.