Re: How can I avoid making this trading mistake? It's giving me a headache
So let's say I dump all the $9,700 into an alt coin for a swing trade. So in this situation, I'm already down $300. I am not happy. Let's say hypothetically, the alt coin I want to swing trade is priced at 45 cents. If the coin goes up to 47 cents and sell, I would have made $431 in profit, but if you actually think about, I would only actually make barely over $100 in profit since I've spent $10,000 worth of ETH in the very first place and value of ETH had gone down. 
You will only know your mistake once you have done it already. That is only your speculation. Stay positive so you can think of a good way.
So what to do now? Proceed in your plan and test it. In the world of trading, it's mandatory to do what you think will be profitable to you because in here we are finding our winning strategy. If the result is not good, then that's the time you will do some analyzation on where you did a mistake. After figuring that out, it needs now some modifications until you will able to get a good result.
Every traders doesn't know what will happened to their respective coins even how professional they are in doing market reading so find a way to deal with the market behaviour out from your self analysis.
P.S Next time, find other way to buy ETH.