What are some really good dua's to make in difficult times?

There are several verses of the Quran that can give you the courage to face difficult situations. Surah Fatihah and Quran Verse 2:177 works for me. However the important thing to remember is that duas gives you inner strength, it will not solve your worldly problems like a magic wand without you actively pursuing the issues with better strategies and devote proportionate time and effort towards their resolutions.