“And let us not be weary in well doing: for in due season we shall reap, if we faint not.”
Galatians 6:9

Let God’s word be the basis with which you make decisions in life, God only recognizes that which is born of his word:
“That is, They which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed.” Romans 9:8
So do good AND expect a reward, because God’s word says you should, and when that becomes your sole reason then the actions of people wouldn’t be a condition in your keeping his word. Always remember that God pays attention to you and all that you do, Jesus was conscious of this and you should also:
“And Jesus lifted up his eyes, and said, Father, I thank thee that thou hast heard me. And I knew that thou hearest me always…” John 11:41-42
Some good things you do would immediately be obvious to others as well as the corresponding reward and some others cannot be hidden. [1 Timothy 5:25]
Set your expectations for your reward higher than earthly things- God is your exceeding great reward, and doing the word means you’re becoming more like him in your expressions; that’s some reward!