A Few Mistakes to Avoid Making with Alt Coins.

1. Always do your own research on a coin and its purpose; Many new people to crypto will blindly invest money into coins they hear about, without actually knowing the purpose and effectiveness of the coin. This often leads to people investing large amounts of money into subpar coins and seeing little to no growth (profit).
2. Avoid Pump-N-Dump's; Pump and dump is a method used by people where simply a large number of people purchase a coin, thus raising the price, they will rely on new (or timid and uncertain) crypto users to buy this in fear of missing out (FOMO). PnD's typically aren't very useful for making money and can often lead to significant losses if you don't buy/sell at the exact time.
3. Don't always believe FUD (Fear, Uncertainty, Doubt) or rumours; For this I will simply use two of the biggest recent examples of both.

FUD:

MarQuis Trill ( @6BillionPeople) released messages from him and verge workers saying that verge was a scam and was going to crash soon, this sent everyone into a panic mode, selling their XVG and driving the price ridiculously low, Trill then bought around 1,000,000 XVG ( $60,000). He then followed up by deleting the post and saying he was hacked and there was no verge crash coming.

Rumors: It was rumored the altcoin XRP (Ripple) would be added alongside the main coins on coinbase. This rumor was seen all across the crypto space and caused many users to panic and buy XRP, causing the price to skyrocket from $0.75 to around $3.00+. For those who sold, congratulations. For those who listened to wise words on many and HODL'ed in hope the price would climb to around $5-10, maybe not the same story. Since the quiet noise of the rumors and no actual addition of XRP, the price has fallen to around $1.60 (at the time of this post), meaning any who purchased at $1.60-$3, may be a tad upset and tad bit in the negatives.