日（ひ、か、ニチ、ジツ）

Meaning: sun, day, Japan

My hack: OK, this is supposed to look like the sun (a circle with a dot in the center), just squished into a rectangular shape. To me it looks just like a window, so I try to imagine that it’s really sunny outside this window, and the focus of this kanji is the white part, not the black part. You have to be careful that you don’t start thinking that it means “window” though!

文（ふみ、ブン、モン）

Meaning: sentence, literature

手（て、シュ）

Meaning: hand

天（あめ、あま、テン）

Meaning: heavens, imperial, sky

円（まる·い、エン）

Meaning: circle, yen

Components: 冂 (same)

My hack: Yen coins are all the same (first 2 strokes to make enclosure), except for one (third stroke) that has a circle in the middle (last stroke going across enclosure).

Since the kanji itself is not all that round, I just remember the meaning by thinking of a round one-yen coin.

六（む、ロク）

Meaning: six

Components: 亠(pot lid), katakana ハ or 八 (eight)

My hack: You could remember it as eight 八 minus 2 strokes (亠). OR, try imagining how well this fits into a hexagon.

五（いつ、ゴ）

Meaning: five

My hack: You’ll have to visualize this one. Focus on the stroke order of this character, and think about how you write the numeral 5. If you start with the top horizontal line like many people do, then this character is just a Picasso version of a 5. Try writing it a few times and I think you’ll see what I mean.

If you need to see the stroke order, try this site.
This also looks like the “warrior pose” in yoga. Maybe you do yoga at 5PM?

中（なか、チュウ）

Meaning: center, inside, middle

My hack: This looks like a morsel of food on a skewer. You always put the skewer in the middle, or the food will fall off.