Buying at key support and resistance levels is how I get sniper entries, especially when I want to swing trade, even though it takes a lot of patience to wait for price to reach these levels. It's a very good way to catch some good waves and make good profits.
I use trendlines too, but right now I use supply and demand zones they're the best things that ever happened to me in forex, I can use it on scalping, swing trading to get very precise entries or I'll just keep my orders around there if I'm not around to execute the order.