It would be better to hold your bitcoins since its price is steadily raising.but if you wish to invest in altcoins and increase your bitcoin volume,then you should try to find the most under valued coin and invest in it.Or else,you should go with coins which were already in the market for more than two years.That would be safe.Since in altcoin market,most coins are just pumped and dumped,you should not follow the market blindly and should not get panic and sell or buy coins due to FOMO.Follow the rule,"Dont put all your eggs in the same basket" and invest in two or more coins.Follow the other rule given by warren buffet,"Buy when every one sells and sell when every one buys".