Time is not so precious that you can't take a few minutes and make sure of your word usage. If you have a question about which word to use, check it out with an online dictionary. If that doesn't supply the answer, do a Google search using all possible options. An example to plug into the Google search bar might be "too vs to vs two." Lots of hits will lead you through the decision making process. I swear, you will learn which word to use in any circumstance.
Since word processors and spell check came into existence, people have forgotten how to spell. That darned spell checker does NOT know more than you do, or more than you can at least learn for yourself. Spell check should be the last resort. If the wavy red line comes up, research for yourself why the computer thinks you're wrong. Quite often, you're simply using a word that the programmer forgot to put in the spell checker's memory. If the computer is right, learn why on your own, don't just depend on the machine. Mastering grammar and spelling so that you can manipulate them to greatest effect will greatly improve your writing, and your reading comprehension.