When choosing altcoins to buy, I consider several key factors. First and foremost, I evaluate the project's fundamentals, including its underlying technology, team expertise, and real-world utility. I look for innovative ideas and solutions that have the potential to disrupt industries or address existing problems. Additionally, I assess the project's community and ecosystem, as a strong and engaged community can contribute to long-term success. I also analyze the coin's market liquidity and trading volume to ensure it is easily tradable. Lastly, I keep an eye on market trends and news, considering factors like regulatory developments and partnerships that could impact the altcoin's future prospects. By considering these factors in combination, I aim to make informed decisions when selecting altcoins to invest in.