Divergences are very effective in showing continuation or reversals in trends but are most effective the higher the time frame. I have been trading BTC the last couple of days so this is a lower timeframe but when you find them on daily or multi-day timeframes they hold even more weight.
Here is a great video on RSI and it also goes into discuss divergences as well. At 34:16 he begins to discuss divergences.
Good Book: https://www.amazon.com/Technical-Analysis-Financial-Markets-Comprehensive-ebook/dp/B00BWVKM4U
If getting started into Technical Analysis then I would advise YouTube. A lot of stuff on there is very good.
This guy has a lot of helpful YouTube videos and does a lot with crypto: https://www.youtube.com/user/carpenoctom
But Youtube is great, start with understanding price patterns, how to read candlestick charts, support and resistance levels and move up from there. The list of studying I took...
Price and candlestick charts, support and resistance levels, pricing/candlestick chart patterns, volume profiles, moving averages and exponential moving averages, oscillators (like RSI and Stoch RSI), Ichimoku cloud, fibonnaci retracements, etc. Start small and work up.