First things first, for you to be able to acquire or obtain altcoin, you have to choose upon those methods you have listed above between investing into an ICO or by means of trading. By those, you can acquire or have varieties of Altcoins that are existing on the market. By means of investing, you need to join or engage into an ICO to obtain a type of altcoin provided or offered by the said ICO. By means of trading, you can purchase altcoins by means of Bitcoin as a trading pair or Ethereum as well or the other types of existing altcoin to obtain other types of altcoin you desire to have. The process or method of holding is maintaining the altcoin you have in which after obtaining varieties of altcoin, you will now be preparing to make your decision if you will just stock it for a while to increase the price and go trade it to obtain or earn income from it. Those are what the things I most likely do to increase or grow my altcoins up.