Look for a sequence of 3 letters that is common throughout the text. This sequence of characters could likely be considered to be the word 'the'. If you successfully figure out which letters Ricky used for t h and e you will be closer to finding out how to decrpyt the code. Also, look for one letter that always follows the amount of letters that most commonly make up a word (for example, some of the most common words are 3, 4 and 5 letters long, and if there is one character that almost always follows these, you may be able to figure out that it is 'I', because 'I' is used very commonly...especially in documents regarding oneself). Numbers found in the text may actually be numbers, and he may be using them to write down an address. Search for two letters that are always in sequence, these could represent the word 'my'. I would suggest doing this same tactic to find all the words that are most commonly used in documents. I hope this helps. Also, it does not always have to be that one character represents one letter, a combination of two characters could be representative of one letter.
