TIP: Upload Videos atleast twice a week, my Uploading Days are Friday and Sunday, sometimes possibly I upload on Wednesday!!
Write huge story of description, throw in all the links, the links can be ur previous videos, ur facebook page, ur Vines, instagram, twitter etc.
Put SUBSCRIBE button at the end of the Videos, it looks professional. NOTE: If u say in ur Video "PLZ PLZ PLZ SUBSCRIBE" it may become a bad impression, it seems like u r looking for SUBSCRIPTION, just say "Waazzup people, wanna catch my more updates aan??? EASY Subscribe Button is here"
Annotations is important as well, it works like a linker or tagger, so better use it for more advantage.
OK PEACE