That's just how it is, Bitcoin has a large number of trading volume, many investors because of its long existence which makes the transaction fees more than others but I've noticed that the fees usually drop at night.The high transaction fees are due to the increased activities on the bitcoin network. The best you can do is try several times of the day and you may just get lucky to get a favourable and cheaper rate sometime. Alternatively, you can work with the altcoins with lesser fees.