of course i agree with you long term trading is very hard and i say that we work in market with market current situation and we make our good technical and fundamental analysis in market and we make good trading experience in market and we make good knowledge in market and we when trader work in market with clear market direction then he/she make good earning easily with forex market
for long term trading strategy, you can use the RSI for it set it to 75 and 25 for overbought levels and oversold levels respectively and use it on the daily chart only as it sometimes does not work sometimes.