I did read the stickied "newbie thread" in this forum, which to my disappointment dismissed "almost all" altcoins as "pump and dump" schemes built on hype. This seems to be quite cynical to me, as from my observations most of the coins that get "pumped" end up stabilizing at levels far above their initial value, even after the correction.
I don't think you understand just how many altcoins there are. There are literally thousands of completely terrible altcoins being created all the time which are just rip offs of Bitcoin or rip offs of another specific alt. All of them think they're better than they are, many of them die very quickly, many of them scam everyone and take the money, many of them get pumped and dumped before they die. You'd be surprised how much money goes into those from naive investors thinking they'll get rich. Poloniex only lists at least slightly legit coins, they don't list every little coin but still the majority of the coins on there get pumped and dumped a lot, and it's very hard for you to profit from those or predict when they're going to happen.
Coins like Ethereum and Monero are different because they have actual purposes - Ethereum is more of an investment system as I understand it (but I don't understand it very well and a lot of people just treat it as another cryptocurrency) while Monero has much stronger anonymity than Bitcoin and is used a lot of the dark web. Some of these coins have started crashing already though - DASH was crap from the beginning, it was clearly a pump with the sudden rise to about $100 and it's already fell to about $60. With this kind of coin that isn't very good but is marketed well enough to be popular, you just need to get in early and sell as soon as the price flattens out a bit. With some coins, you'll have to sell while the price is going up, and ignore the potential that it'll go higher because it's just too risky.
Tips:
-You need to research the coin and how they distinguish themselves from other cryptocurrencies (and why that'll bring them more investors).
Don't take meaningless explanations claiming that it has instant, anonymous transactions, and don't take explanations if you don't fully understand them. You should also ideally research the developers' history and anything you can find out about them so that you know it's not a scam (to be fair, not a lot of altcoins with any significant marketcap are scams which aren't obvious).
-You need to find the altcoin's subreddit. Reddit is huge on altcoins and the altcoin should have a subreddit where they're likely to post information often. You should also find the altcoin's
ANN thread - all good altcoins have ANN threads on Bitcointalk, often before they're even released, so that should help you to get in early to a good coin, but don't jump on the first coin that appears. Wait for peer review and feedback from other forum members (is it premined? Is it a copy of another coin?) and you can use that information to help you make your own decisions later on.
-Don't hold all of your money in an exchange, keep some of it in an offline wallet called a software wallet (research that yourself), because Bitcoin related exchanges are pretty notorious after what happened with Mt. Gox.
-Don't jump on altcoins that are rising if you don't understand the graphs. Trust me, you'll fail. I've tried it.
-If you want simplicity, you don't have to trade your altcoin with Bitcoin. You can trade it with
USD Tether (USDT) which is a cryptocurrency permanently tied to the value of a US dollar. This way, it'll be clearer how the altcoin charts are moving because it'll be against something more stable.
If you find a legitimate coin's ANN thread, it might be an ICO (Initial Coin Offering) which will let you put money into the coin and end up getting coins when the coin is created. This is getting in really early, and if you find a good coin, it could be profitable. Be aware of ICO scams, which happen regularly.
Sorry for the wall of text.