一點(diǎn)and 有一點(diǎn) are two different phrases with different meanings. They may be associated in a way if you look at the characters in them, but they don't mean the same thing at all and are used very differently

First, 有點(diǎn) is actually the shortened version of 有一點(diǎn)

Before giving the "technical" explanations for 一點(diǎn) and 有一點(diǎn), I'd like to give you some examples in which each one is often used, in order to enable you to grasp a natural feeling about these two language elements.

For 一點(diǎn)：

（if you see the character“有” in these sentences, consider it as "have" or "there is", and note that it's entirely not the same as in the phrase "有一點(diǎn)"）

1. 我需要一點(diǎn)時(shí)間

I need a little time

2. 她每天都看一點(diǎn)書

She does some reading every day

3. 廚房里有一點(diǎn)食物

There is some food in the kitchen (perhaps not much)

4. 請喂它點(diǎn)水喝

Please feed it some water

5. 我需要放多少鹽君纫？- 一點(diǎn)就夠了

How much salt do I need to add? - A small pinch will do

6. 有時(shí)人需要一點(diǎn)運(yùn)氣

Sometimes one just needs some luck

7. 可以再給我點(diǎn)咖啡嗎罕邀？

Can I have some more coffee?/ Could you give me some more coffee?

8. 要有一點(diǎn)信念

Have some faith

9. 我只有一點(diǎn)錢

I only have very little money

10. 我從這個(gè)課程中只能學(xué)到一點(diǎn)知識

I can only learn very little knowledge from this course

11. 我一點(diǎn)錢也沒有了

I don't have a single penny now

12. 我一點(diǎn)東西都不想吃

I don't want to eat anything at all

Feel free to linger on these sentences, read them out if you can, because it really helps

Now as you may have already found out, the phrase 一點(diǎn) is very similar to "a little/some" in English, it indicates a small amount of something, especially uncountable things. It is way less often used to describe countable nouns(How do we describe a certain amount of something that is countable? Let me know if you wanna know). Usually, 一點(diǎn) doesn't necessarily mean a very small amount, it can also mean "some". But if you want to clarify that you're talking about a really small amount, say 一點(diǎn)點(diǎn). For example:

我這個(gè)天空的顏色對嗎？- 再加一點(diǎn)點(diǎn)藍(lán)色就好

Does the colour of my sky seem right? - You might want to add the least touch of blue

Moreover, it can sometimes be used to emphasize a really really small amount of something, perhaps not enough to do anything with it. In this case, the character "只" is usually used before it, as in sentences 9 and 10

Additionally, when it's used in a negative way, such as "一點(diǎn)……都不", it means none at all, as in sentences 11 and 12

Some useful variations of 一點(diǎn):

(This is something useful and interesting but not necessary, so it's okay if you don't want to memorize the following explanations):

It is especially common to simplify 一點(diǎn) as 點(diǎn). Usually, they are completely interchangeable. If I must point out some difference, I would say "一點(diǎn)" sounds slightly more formal and sometimes with more emphasis, but not always. Hence, if you look at the sentences from 1 to 8, you can absolutely replace 一點(diǎn) with 點(diǎn) in every sentence, but NOT in sentences like from 9 to 12 (because in 9 to 12 "一點(diǎn)" means a little bit differently with more emphasis on the scarcity).

Also, people like to add a special sound after the character 點(diǎn), it sounds like "er" in "mother" in American English. We use the character 兒 to stand for this sound. This is true for all circumstances, people speak with this sound all the time. From sentence 1 to 12, you can add the sound "er" in each one of them. You can hear what it sounds like in my voice messages in Tandem

So when you see things like 一點(diǎn)朴沿，一點(diǎn)兒躺彬，點(diǎn)凭舶，點(diǎn)兒, just remember they mean exactly the same thing and are often completely interchangeable in sentences like from 1 to 8

For example,

我需要一點(diǎn)時(shí)間

我需要一點(diǎn)兒時(shí)間

我需要點(diǎn)時(shí)間

我需要點(diǎn)兒時(shí)間

These four sentences mean exactly the same thing

For 有一點(diǎn)：

1. 天氣有點(diǎn)熱

It is kind of hot today

2. 我有一點(diǎn)冷

I'm feeling a little cold

3. 這道菜有一點(diǎn)咸

This course is a bit salty

4. 她男朋友有點(diǎn)壞

Her boyfriend is a bit mean

5. 我有打擾到你嗎？- 有一點(diǎn)

Am I bothering you? - A little bit

6. 我今天有點(diǎn)不舒服

I'm not feeling very good today

7. 她有點(diǎn)難過

She's kind of sad

8. 我有點(diǎn)想辭職

I'm considering quitting my job

9. 今晚我有點(diǎn)想看電影

I wanna watch some movies tonight

10. 你是不是有點(diǎn)想睡覺堕扶？

Are you hoping to get some sleep?

11. 我有點(diǎn)不喜歡寵物

I don't really like pets very much

12. 我有點(diǎn)討厭抽煙的人

I kind of hate people who smoke

有一點(diǎn) indicates someone or something has certain attributes/emotion/intention to a limited extent or in a mild way. It works like an adverb in a sentence.

That also makes 有一點(diǎn) become a very useful phrase to euphemistically express something or someone has some attributes/emotion/intention, even if it isn't mildly, we just say 有點(diǎn) to sound less rude.

Note that the thing after 有一點(diǎn) is usually something unpleasant or something that may cause troubles or bad influence. That's why we use 有一點(diǎn) to say it in a euphemistic manner. Or it can also be used to convey a euphemistic request, showing that you want to do something. Or you can use it to say you're considering doing something but haven't made up your mind yet.

Variations:

Just remember that 有一點(diǎn)，有一點(diǎn)兒梭依，有點(diǎn)稍算，有點(diǎn)兒 all mean the same thing and are usually completely interchangeable

If you're trying to be euphemistic or polite, 有點(diǎn) is absolutely more often used than 有一點(diǎn)(perhaps because it is less formal)

Let me know if you have further questions