“But to do good and to communicate forget not: for with such sacrifices God is well pleased.”  
Hebrews 13:16

In the preceding verse he said:
“By him therefore let us offer the sacrifice of praise to God continually, that is, the fruit of our lips giving thanks to his name.”  Hebrews 13:15
It means when things aren’t going the way you seem to want them to go, when things are happening around you and there seem to be nothing to thank God or be joyful about; it’s offering time!
At that moment when everything seems bleak, God says present your offering; that sacrifice of praise. Your body might not feel like it, that’s why it’s a sacrifice; praising God when it seems you have no need to praise, but praising him as a sacrifice, in faith, knowing:
“…he hath said, I will never leave thee, nor forsake thee.”  Hebrews 13:5
He explains what this sacrifice of praise is- the fruit of your lips, giving thanks to his name. You don’t spend the time weeping for sorrow or complaining, he said instead give thanks to his name, every word of thanks you give is a sacrificial fruit- thank him for that glorious name of Jesus; that name that has the final authority and is always available for your use.
Then he said, in all of that, do not forget to do good- don’t think because you feel things are tough, you have to be selfish or nonchalant, he says as you offer your sacrifice of praise, you should always remember to do good and to give: “… for with such sacrifices God is well pleased.”