as far as food...
my spots are as follows
green leaf in the international district for vietnamese food. so good. get the combo vermicelli food. green leaf is probably my favorite restaurant in seattle.
taste of india in the U district for indian food.
paseos in fremont for pulled pork cuban subs and other carribean delicacies. amazing food, long lines, cash only, but WORTH IT!
thai tom in the u district for thai food.
ezells chicken in the central district from some fried chicken.
tubs subs in lake city for some great sandwiches.
canlis in queen anne for some really fancy expensive food. view of the whole city and #%$#. take your girl here if you really want to moisten panties.
palace kitchen near belltown is a cheaper option for a fancy delicious meal. its done by tom douglas, one of seattle's most successful and famous chefs.
pudge brothers and pagliaccis, both u district for pizza.
any gyro spot for some good gyros. especially mr gyros up in greenwood and ballard. its the best.
any teriyaki spot for some good teriyaki. especially i love teriyaki in fremont.
****'s drive in for late night burgers. open till 2 am, cash only. there are several locations, u district, capitol hill, right near the space needle. get a deluxe, fries and a milk shake.
red mill for a slightly fancier burger. faaaaantastic. anyone who tells you otherwise is tripping. they make the best burgers in seattle, plus the best onion rings in the country. according to vanity fair.
[font=Arial, Helvetica, sans-serif]and lastly my favorite place, SKILLET DINER. a gourmet take on traditional diner food. its in capitol hill and would make for a great meal before going out in that neighborhood. [/font]
as far as tourism goes, i know ride the ducks is super popular for out of towners. you ride amphibian vehicles that ride on land and in the water. i wouldnt do it cause im a local but its a great way to see alot of the city, including some of the lakes. do that on a nice day.
[font=Arial, Helvetica, sans-serif]gasworks park is an awesome park with a view of the whole city and lake union to check out, and its pretty close to paseos so you can knock those two out in one. probably the best view and the best sandwich in one. kerry park in queen anne for another picturesque view point. [/font]
for night life, capitol hill is a pretty diverse place with a lot of nightlife, slightly on the hipster side but definitely overbearing. there are all kinds of bars there. its usually my spot when im going out. keep in mind there are a decent amount of gay people there but if you're a homophobe you probably shouldnt go to seattle. u district for frattier college bars (its right near the university of washington) ballard is similar to capitol hill with a slight hipster tinge but a little mellower. a lot of cool bars there. fremont is like the u district in that it is kind of fratty but it is a slightly older crowd. belltown is near downtown and its kind of gross. has potential but its filled with a lot of crackheads and douchey guys who want to fight. it's where you're most likely to get in a fight. judging from your lin avatar i assume you're asian. i'm not big into clubs but there are some popular ones downtown and in SODO, including some that allll of my asian homies always roll to. check it out if its your thing.
if its nice out, i would suggest getting some bikes and riding around. seattle is a very neighborhood oriented city so there is a lot you will naturally miss out in only three days, but i suggest picking a few of the aforementioned neighborhoods and kind of exploring them well. when i visit a city i am alllllll about food so that is my main perogative and how i plan out my days.
i love seattle, i've been all over the world (humble brag) but something about this damn city just keeps me coming back. i love talking to people about it and sharing the wonders and all that fairy #%$# so if you have any other questions feel free to PM and i would happily answer them. enjoy seattle. one.