Like you said, when you think the price is low, thats when you buy. Bitcoin hasn't been at $1,000 in about 2 years. I have doubts that it will get that low in the near future. The fact that you don't know that means you have a long ways to go (not trying to be mean). People think crypto is this get rich quick thing. It can be at times, but its just like investing in the stock market. Its all about luck and having the bigger stack of money. No one in the world can predict the price accurately. Its all luck and making educated guesses. I recommend you first paper trade. Meaning, just pretend like you have $10,000 and try and make pretend trades with that $10,000. See how you go.
4 great resources to use is, trading view (for bitcoin charts), coinmarketcap (simplified data about lots of coins), google trends (see how popular crypto currency is, worldwide) and cryptocurrency reddits (to see how everyone else is feeling).
In cryptocurrency there can be a 5% difference in price in matter of minutes.
Its the well known coins with the littlest room for growth in terms of price. For example, the price of bitcoin essentially 20x in the year of 2017, but ethereum 100x. So even if bitcoin hits $20,000 this year, its essentially just a 4x this year. The other top coins have the biggest room to grow in. Usually the trends is, when bitcoin goes up in a bullish market, the alt coins go up by more.
The best place imo is a hardware wallet like Trezor or Ledger. However, blockchain is still good. Wouldn't recommend a hardware wallet unless you have lots of money.