Я редко крашусь ярко, но иногда наношу тушь и немного помады.

In this sentence, крашусь comes from краситься, which means to put makeup on oneself or sometimes to dye one’s hair.

The -сь shows that the action is directed back to the subject:

• красить = to paint/dye something or someone
• краситься = to paint/dye oneself, to put on makeup

So:

• Я крашу стену = I paint the wall
• Я крашусь = I put on makeup / I do my makeup

Here it specifically means I wear/apply makeup.

Yes, that is the idea.

Крашусь ярко literally means something like I make myself up brightly, but in natural English it usually becomes:

• I wear bright makeup
• I do my makeup boldly
• I put on noticeable makeup

So ярко describes the style of the makeup: strong, vivid, noticeable, not subtle.

Because ярко is an adverb, and here Russian needs an adverb.

It describes how the person does her makeup:

• Ярко = brightly, boldly

If you used an adjective such as яркий or яркая, it would need to describe a noun:

• яркий макияж = bright makeup
• яркая помада = bright lipstick

But in the sentence there is no noun after it. It modifies the verb крашусь, so the adverb ярко is correct.

Russian often uses the present tense to talk about habits or usual behavior, just like English does.

So this sentence is not about one specific moment. It means something habitual:

• Я редко крашусь ярко = I rarely wear bright makeup
• но иногда наношу... = but sometimes I apply...

This is sometimes called the habitual present.

Both крашусь and наношу are imperfective because the sentence describes repeated or habitual actions, not single completed events.

Imperfective is normal for:

• habits
• repeated actions
• general statements
• processes

Compare:

• Я редко крашусь ярко = I rarely wear bright makeup
• Сегодня я ярко накрасилась = Today I put on bright makeup

In the second example, накрасилась is perfective and refers to one completed action.

Тушь is the direct object of наношу, so it is in the accusative case.

However, for many feminine nouns of this type, the accusative singular looks the same as the nominative singular.

So:

• nominative: тушь
• accusative: тушь

That is why the form does not visibly change.

Because немного requires the genitive case.

So:

• немного чего? = a little of what?
• помада becomes помады

This is a very common pattern in Russian:

• немного воды = a little water
• немного сахара = a little sugar
• немного помады = a little lipstick

So even though lipstick is what is being applied, after немного Russian uses the genitive.

Because Russian often omits the subject pronoun when it is already clear from the verb form.

In this sentence, the first clause already gives the subject:

• Я редко крашусь ярко

Then the second clause continues with the same subject:

• но иногда наношу тушь...

Since наношу clearly means I apply, repeating я is unnecessary.

You could say но я иногда наношу..., but it is not needed here.

Но means but and gives a clearer sense of contrast.

The contrast is:

• I rarely wear bright makeup,
• but sometimes I do apply mascara and a little lipstick.

Using а would sound more like a comparison or a softer contrast. It is not impossible, but но is the more straightforward choice here because the speaker is contrasting two tendencies.

Yes, the given word order is natural, and Я редко ярко крашусь is also possible.

Russian word order is flexible, but different orders shift emphasis slightly.

• Я редко крашусь ярко = neutral, natural
• Я редко ярко крашусь = also natural; slightly more emphasis on ярко
• Я ярко крашусь редко = more marked, more contrastive

For a learner, the original version is a very good standard model.

It can mean more than one thing, depending on context.

Краситься can mean:

• to put on makeup
• to dye one’s hair
• more generally, to color oneself / make oneself up

In this sentence, the context makes it clearly about makeup, because of:

• ярко
• тушь
• помады

So here nobody would think it means dyeing hair.

They are related, but not identical.

• крашусь is broader and more general: I do my makeup / I wear makeup
• наношу is more literal and specific: I apply

So the sentence first makes a general statement:

• I rarely wear bright makeup

Then it becomes more specific:

• but sometimes I apply mascara and a little lipstick

This combination is very natural in Russian.

Yes. Крашусь is very common and natural in everyday speech, but there are more formal or explicit alternatives.

For example:

• Я редко делаю яркий макияж = I rarely do bright makeup / wear bold makeup
• Я редко пользуюсь ярким макияжем = I rarely use bright makeup

Still, Я редко крашусь ярко sounds normal and idiomatic in conversation.