明日の百より今日の五十 - A bird in the hand is worth two in the bush.

明日の百より今日の五十
A bird in the hand is worth two in the bush.
Better an egg today than a hen tomorrow.

In japanese,

Fifty today is better than one hundred tomorrow.

明日は明日の風が吹く - Tomorrow is another day.

明日は明日の風が吹く
In Japanese, it is said; Tomorrow, another wind will blow.
  

 
Negative phrase using tomorrow ;
Tomorrow never comes.
Never put off until tomorrow what you can do today.　
Better an egg today than a hen tomorrow.　 

朝飯前 - It's a piece of cake.

朝飯前

It's a piece of cake.
As easy as pie
As easy as ABC

悪銭身につかず - Easy come, easy go.

Easy come, easy go.

 

逢うは別れの始め - meet only to part

逢うは別れの始め

Meeting is the beginning of parting
We meet only to part.The best friends must part.
We never meet without parting.


 

若気の至り youthful inexperience

Couldn't you overlook it as an act of youthful inexperience?
若気の至りと大目に見ていただけませんか？

来年のことを言えば鬼が笑う。 devil will laugh

Talk about the next year, and the devil will laugh.
来年のことを言えば鬼が笑う。