Hm. Well first I'd be excited as hell that I got asked out at all lol It definitely depends on the individual's personality. I'd want more of an intimate conversation, no texting or huge banners or anything..
Depends on a lot of factors. But I'll narrow it down to two (assuming you didn't post details for a reason). If you know the person well and are good friends to best friends, I would be super honest about how you feel about them, and why, so they know that this is important to you. Be sweet, but don't come off too strong. And then ask very directly, in any situation. It needs to be crystal clear that you are asking them out, not just what YOU would perceive as obvious, something universally obvious. Such as (after an eloquent preface of course) "Would you like to go on a date with me?" and if you know them well, think of a specific date they would like. Like " Would you like to go to *their favorite restaurant/ place they've been wanting to try* and then see *funny movie they mentioned wanting to see*? And then if they say yes, name a day and time. " or if its more of a low-key date "Would you like to come over, watch *show you both like* and eat *their favorite food/dessert*?". If you don't know them well, then Id say it depends on what goes with your personality. If you're a grand gesture kinda person then maybe do flowers, or a cute note in an unexpected place (locker, bag, etc), or if you wanna get creative bake a cookie and write "will you go out with me?" or something to that effect on it, or write the question and put it in a fortune cookie. If it would be very difficult to ask this person out face to face for you, then I would definitely do something cool/exciting to ask them out so that the cuteness is greater than the lack of confidence to do it in person. If you hate grand gestures and aren't the creative type, then I'd be casual and confident about it. Just " Would you like to go on a date with me sometime?" when there's a pause in convo or there feels like a good moment. If this person is intimidated by commitment and likes to take things slow, then I might describe a date without naming it. like "Do you want to go get some food at *romantic/cute place* and then maybe see a movie with me Friday night?" if they ask if it is just you two or anything similar make it clear that it will be "just us". So yeah, hope I maybe stirred up some Ideas or was helpful somehow! Good luck, its sweet that your asking for advice on asking them out. You obviously care. Hope all goes well!