One of the biggest problems is quick texting, messaging. Many of us never use capitals when we send a quick text message to our family and friends. We do this so often that it can sneak up in our writing.
First Words
First word of any sentence needs a capital letter. This doesn't mean that you avoid the full stop, just so you don't have to put a capital in. These rules apply everywhere, even in email and instant messaging.
Direct Quotations or Dialogue
A quotation is pretty much a sentence someone else has said and therefore, needs a capital letter. This is exactly the same for a dialog. But remember that if your quotation or dialogue is still continuing then do not capitalise as it is still part of the same sentence. Example:
“Nothing so needs reforming,” Mark Twain once said, “as other people’s habits.”
Major Words in Titles
When capitalising a title, capitalise all the nouns and verbs, but never the "the," "on," "in", "a" and "if" or any other words such as these.
Countries, Languages, Nationalities,Racial and Ethnic Groups
This heading is pretty self explanatory as you will always capitalise them, the only exception is "black" and "white," but some other grammar guilds would be different.
Names and Titles
When using a person's name you will capitalise it, this goes the same for any titles that is in place of their name "Mom." This is only the case when the title if taking the place of a name or acting as a name. Example:
"I spoke to Dad," "I spoke to my dad" You can't replace your dad's name in the second sentence "I stoke to my Tim" it does not make sense.
Dates, Locations
Anything that is found on a map or calendar is capitalised, but do not capitalise direction. Example:
I live in the North. (This shows location)
I hiked west. (This is direction)
For more rules and a small exercise check out this Link.
Just on a little side note for self improvement. I will be doing pushups, situps and squats for the amount of $$$ (ratio;$1:1) I earn on this post and will give a short feedback every day at the end of each post. This will be split in equally between all 3. Any not done will carry onto the next day.