Hey Hi,
I am Ahsan and i need your support to invest in bitcoin trading, i already used poloniex, i bought DGB there and after holding so many month i got frustrated and sold all in loss

now i want to restart the things again with around $ 1000. so please suggest.
Regards,
Ahsan Holding one coin like DGB or any single coin will give you greater loss. If you are a holder or a trader it is good to have a portfolio instead of investing in a single coin.
You can buy Bitcoin and hold for a longer span as it is halving of BTC in 2020 there are higher changes of BTC pumping up. You can also buy XRP, LTC, XLM, ADA and few top coins for portfolio. If any point of time your strategy says that any coins is about to dump then you can exchange that coin to BTC for example
XLM to BTCAlso, before invest please make sure that you are convinced with the signal you are following. If you have your own strategy then it is very good. Else, you can learn trading on paper trading tools or test net and then go with actual investment.