To find one of the many online references for spelling rules, just google on the key words english/spelling/rules and take your pick.
I know, I know...spelling is a nightmare in English. You'd be amazed at how many intelligent native speakers are poor at spelling. Personally, I blame it on the Romans.
I have always found that one of the best ways to remember how to spell troublesome words is through the use of mnemonics, or memory tricks.
For example, is it recieve or receive? Well, the old expression i before e except after c saves the day. It's receive.
Is it affect or effect? Well, I just remind myself that affect is normally a verb (an action word), so I just remember a for action. Bingo.
Is it message or massage? Well, picture yourself receiving an important message and imagine that it is so sloppily written that you can't read it. It is completely illegible, and has ketchup stains all over it from someone eating French fries, etc. The message is a real mess. On the other hand, imagine you're ready to get a full body massage, and you're lying face down on the table. The masseur (or masseuse, as you please) comes in and begins to massage you. At that point, you turn your head and look and it's your ma (mother) giving you the massage.
And so on. Every time you find yourself struggling to remember how to spell a word, get creative and form a little jingle or outrageous mental picture that will be unforgettable to you that will jog your memory.
Hey, don't laugh...it's either that or just try and memorize every word.
Student or Learner