Seek forgiveness from Almighty Allah and invoking His blessings upon the Prophet and his household (peace be upon them) – “Istighfar” and reciting the "Salawat" – repeatedly are amongst the acts that may cause the duas to be accepted and answered.
There is no doubt that it is permissible to join between Dhuhr and Asr and between Maghrib and Isha as all Muslims have reported that the Prophet (peace be upon him and his holy progeny) has joined between prayers without being in unusual situations of travel or during rainy weather. Performing them separately during their recommended set times is better with the hope that it is desired by Almighty Allah.