Some coins can be mined on regular desktop PCs, others need special hardware (e.g. Bitcoin and Bitcoin Cash can only be mined profitably on ASIC miners).
For the ones that can be mined on desktop PCs, you need both software and adequate hardware - at any given point in time there are only a few graphics cards that are profitable; for example currently the NVIDIA 10 series (1060, 1070, 1080, 1080 Ti) and AMD Radeon RX470/480/570/580 (with a BIOS mod). You can find mining hardware comparisons here - https://www.cryptocompare.com/mining/#/equipment
Rx570
Asic
When it comes to software, the strategy is the following:
Choose which coin you’ll be mining, based on the above site and https://whattomine.com/; input your graphics card in the above boxes, input your electricity cost, and click “calculate” - then go through the list from top to bottom and look for coins with decent market capitalizations.
Search for “coin name pool statistics”.
Find a pool that has a decent portion of the overall network hash rate, but lower than 40–50%.
Go to the pool’s site, register if needed, and check out what settings you need. Make sure their fees and payout thresholds aren’t insane (but if it’s a big pool, they likely aren’t).
Search for “coin name wallet”, try to figure out if they’re OK with sending mining rewards to the wallet, or at least if there’s a safe threshold which they won’t mind (e.g. once per week).
Search for “coin name mining software card model and manufacturer”. In the best case you find benchmarks; there can be big differences between one program and another.
7.Download and configure the software with the pool settings you got from step 4, and if needed the payout address from step 5.
8.Go to the pool’s site and find a way to monitor your progress, set payout thresholds, etc. (if you set the payout address in the site instead of the mining software, do that now).
After you’ve already mined a decent amount, you can register on an exchange like Binance to trade the coin you’re mining against other coins (in case you actually want something other than what you’re best at mining).