Just holder and buy more if you can
Short answer: What he said
Long answer: Look at the 50, 100 and 200 SMA and aim to buy in at the support levels. Don't sell when at new lows. Noobs panic on these correction, HODLers see these as a black Friday sales
One last thing: Don't trade on margin unless you REALLY know what you're doing.
. In few months ago, I just holded Ripple and Stellar in 2 months (I accept high fees from margin) but it made me a big loss and I lossed ~95% my funds (I did not use cut-loss). 