What should you prioritize most when choosing an exchange? Many beginners look at fees first, but the higher priority is the security and regulatory record. The reason is simple: a few basis points of fees eat into your profit at most; an exchange being hacked, collapsing, or freezing withdrawals eats your principal. First confirm its history of security incidents, whether it has user-protection mechanisms, and which jurisdictions regulate it — these are the baseline. Putting money into an unsafe platform makes even the lowest fees meaningless — you first need to be sure you can get the money back, then talk about how much you save.
Does liquidity really matter for beginners? Yes, and more than you'd think. Liquidity refers to the depth of buy and sell orders that can fill smoothly. On a high-liquidity exchange, spreads are tight and your order fills near the expected price; on a thin small exchange, orders are sparse, so the moment you buy the price jumps up and the moment you sell it drops — that "slippage" is a hidden cost. Worse, a too-small platform may have no counterparty to let you exit during violent moves. For beginners, choosing an exchange with ample liquidity in major coins saves a lot of invisible losses.
How do you read the fee structure so the surface number doesn't fool you? Don't look only at the "maker fee." Read all four parts: spot maker/taker fees, contract maker/taker fees, withdrawal fees, and the cost of fiat deposit/withdrawal. The low rate many platforms advertise is just the maker rate, while in practice you're often the taker, at a higher rate. Add withdrawal fees — for some coins these are startlingly high. For high-frequency traders, these add up to a meaningful sum over a year. Computing the total cost "under your actual trading habits" matters far more than the lowest number in an ad.
In practice, how should a beginner start, and how do you avoid putting all eggs in one basket? Three steps. First, start with a large, liquid mainstream exchange with a good withdrawal reputation, run the full "deposit, trade, withdraw" flow with small amounts, confirm it's smooth, then scale up. Second, don't pile all assets on the exchange long-term — an exchange is a custodian; large long-term holdings should move to a wallet where you control the keys, leaving on the exchange only what you'll trade soon. Third, if you trade a lot, consider a second exchange to spread risk as needed. In a sentence: an exchange is a tool, not a safe.