Honestly, the most you can really do to keep it alive is do what it demands, and pray for the best

tamas eat the most and are the neediest when they are first born
most nanos have a way to mute it and some have a way to pause it but it depends on the tama

most nanos require you to turn the tamas light off when it sleeps which is usually around 8-9pm, most tamas wake up around 8 or 9, and offbrands are simpler so they dont sleep, and dont have the job, store, happiness level, or mail function, but offbrands let you choose your pet, but it prolly wont evolve or grow up like most on brand tamas

i wouldnt suggest the angle nano tama bc it has alot of extra features and is hella needy, i got tired of caring for it TvT
off brands usually are easy to care for but feel less rewarding

also tamas make noise and only some of them have ways to mute them, offbrands ussually dont have a mute option or a way to 'pause' the tama so it doesnt die while your at school or smth, so you may need to wrap tape around its speaker to lower its volume

for the love of christ, READ THE MANUAL. Some tamagotchis have special features, animations or needs and youll need to read it to know what they are and what certain things do, save your manual for reference!!!

if your tama is glitching or seems broken, fear not, ive never had a issue with a tama that restarting it couldn't fix (this is usually done by sticking a pencil or smth into this button thats like inside the tama)

a way to make caring for tamas more fun is by taking turns babysitting it with friends (assuming you trust them to keep it alive lol), or taking care of multiple at once!

tamas are hella easy to lose so make sure to keep track of them!

theres lots of different kinds of tamas too, Jurassic park ones, hello kitty ones, kuromi ones, JJK ones, demon slayer ones, a eevee one that only released in japan, and theres lots more if your looking at other tamas besides nano ones!

offbrand ones are way cheaper, ranging from only 1$ to 16$, while official ones are like 20$ (if you wana get multiple for cheap, you can buy them for like 2$ on temu)

last thing : Nanos are only supposed to live for 14 to 24 days! so dont be sad if your tama passes, its a part of the cycle! tho more modern tamas wont die i think (also not all tamas 'die', my hello kitty one 'moved to london' when it reached max time bc i took good care of it and then i started over)

(btw this whole yap sess is for nano tamas specifically, they are the smallest tamas and ive ever had others besides off brand tamas which resemble nanos anyway)