One of my grammar issues

I do know the proper use of their, there and they're. I know when to use to, too and two. Quick typing and lack of proof reading don't always guarantee the correct outcome in my posts, but I usually catch mistakes later and flinch. I hate improper use of these words. HOWEVER, there are several areas that consistently cause me confusion. One of the biggest is knowing when to use effect or affect. I found this website, which links to this website. I plan to study them both until I have it all worked out. Then I'll move on to my next problem area.