Adding a prefix or a suffix: racist, diskette, biohazard, biometric, reskill, dollarize etc.
Using part of a word: exam, admin, ammo, info, intro, limo etc.
Joining words: cashback, upskill, blowback, supersize, flashlight etc.
Changing the way a word is used e.g. a noun becomes verb: to chair, to refund to reject, to survey, to suspect, to progress, to escort etc.
Words made with rhyming pairs: ping-pong, heebie-jeebies, willy-nilly, eager beaver, boogie-woogie, teensy-weensy, hush-hush, zig-zag etc.
Forming a word from the letters of a phrase: scuba, radar, laser, nasa, snafu etc.
Mixing words: brunch, britpop, chocoholic, hardscape, agroterrorism etc.
Taking a word from another language: pinky, yacht, brick, typhoon, ghoul, massage, model, sushi, vodka, cigar etc.