Suffixes called diminutives are added to words to indicate smallness, affection, humor, pity, irony, or ridicule. Some examples in English are:

book --> booklet (small book)
lad --> laddie (small lad)
man --> manikin (small man)

Some common Spanish diminutives are: -ito, -cito, -ecito, -illo, -cillo, -ecillo

Note that diminutives change to match the gender and number of the word they modify. For most words, we drop the final vowel and add -ito or -illo.

Examples:

ahora - now ---> ahorita - right now
hermano - brother ---> hermanito - little brother
Juana - Jean ---> Juanita - Jeannie

Let's look at some example sentences:

Mi hermanito tiene cinco años.
My little brother is five years old.

En invierno le pongo suéter a mi perrito.
In the winter I dress my little dog in a sweater.

No paramos para comer, así que tenemos hambre ahorita.
We did not stop to eat, therefore we are hungry right now.

Sí, señor. Ahorita se la consigo.
Yes, sir. I'll get it for you right away.

La librera era de mi abuelita.
The bookshelf was of my dear grandmother.
The bookshelf was my dear grandmother's.

¿Usted cree que esté allí ahorita?
Do you think he might be there right now?

Words with more than one syllable that end in E, N, R, or a stressed vowel take -cito or -cillo:

Examples:

una joven - young girl ---> jovencita - young lady
mamá - mama ---> mamacita - mommy
pintor - painter ---> pintorcito - poor painter
pobre - poor ---> pobrecito - poor little thing

El ratoncito es marrón.
The little mouse is brown.

Ayer tuve un dolorcito.
Yesterday I had a little pain.

Házlo despacito.
Do it very slowly.

El niñito abrazó con sus bracitos a la mamá.
The little boy embraced his mother with his little arms.