Verb reduplication (1)
Verbs denoting an action that can be repeated or continued may be used in a reduplicated form.
Reduplicating a verb usually conveys:
that the action lasts a short while;
that it is done just a little;
or the sense of giving it a try.
The form gives the sentence a light, easy, softened tone and belongs mostly to spoken Chinese.
The forms
1. One-syllable verbs
A（一）A
verb + (一) + verb
For example:
想一想 — have a think
2. Two-syllable verbs
ABAB
For example:
休息休息 — take a bit of a rest
3. Separable verbs
AAB
For example:
帮帮忙 — lend a hand
Examples
那你再想一想，你想好了，我来买票
那nàthen
再zàiagain
想一想xiǎng yì xiǎnghave a think
想好了xiǎng hǎo lehave made up one's mind
我来买票wǒ lái mǎi piàoI'll buy the tickets
Here 想一想 means a short think, not a long deliberation.
我有点儿累，现在想休息休息
我有点儿累wǒ yǒudiǎnr lèiI'm a little tired
现在xiànzàinow
想xiǎngwant
休息休息xiūxi xiūxitake a bit of a rest
Here 休息休息 shows that the rest will be brief.
你能过来帮帮忙吗？
你能nǐ néngcan you
过来guòláicome over
帮帮忙bāngbang mánglend a hand
吗maquestion particle
Here 帮忙 is a separable verb, so its reduplicated form is 帮帮忙.
Quick rule
Reduplicating a verb usually makes the action lighter, shorter or tentative.
One-syllable verb — A（一）A: 想一想 — have a think
Two-syllable verb — ABAB: 休息休息 — take a bit of a rest
Separable verb — AAB: 帮帮忙 — lend a hand