If you want to trade and not loose that much trade with a very stable altcoin dont trade if it the specific coin has a problem.
But with so many altcoins out there, how will you know that there are good? And I believed that there are no stable altcoins because they are much volatile than bitcoin. There are numerous pump and dump group that target specially a coin and even if this coin has no problem it will go the fate of others once a group has pump it up. I think the most safe strategy is just invest what you can afford, so that if something went awry, you will not be affected that much.
When a trader is going for altcoin trading then definitely he cannot expect trading safely. Because altcoins are known for high manipulations at any time, you cannot be sure what is going to happen after you will be entering that is the reason I never prefer going for new altcoins.
Just sticking with bitcoin trading definitely ensures trading safely. There are people who are making profits with altcoin trading too, but I'm sure they cannot make similar profits consistently. Moreover, altcoin trading is very much similar to gambling.