Try to relate them with some famous dates, like your birthday; you first date to join school. Then make groups. That how many dates are in Jan., Feb. & so on. Try to remember one date every day. Write it for several times on your note book.
Connecting dates with each other is also helpful. For example, East India Company took first victory capturing Bengal in 1757 and right after 100 years in 1857, there was War of Independence and Company was resolved to take India under British Rule completely. Here number “57” resembles.
And Fall of Muslim Spain and Discovery of America by Columbus happened the same year i.e. 1492 CE.