Think about what you want to say in the letter. The letter could be a declaration of your love or simply express your excitement at your future together. Or, tell your girlfriend personal things you feel unable to say in front of her.

Write down a list of key things you want to say to focus your thoughts. This will help the letter sound more coherent. Include why you are writing the letter, your feelings towards your new girlfriend, and two or three compliments about her.

Begin the letter with a personal tone. For example, instead of writing "Dear Susie," use an informal style of address such as "Susie, my sweetie pie" or a particular pet name you have for her.

Start writing by expressing your happiness or positive thoughts about her. This will put your new girlfriend at ease while she reads the rest of the text. For example, begin by writing "I am really happy we finally got together because I adore your sense of humor."

Introduce the main idea you want to communicate in the letter. Explain why you are writing. Write, "I have decided to put pen to paper to tell you that...."

Continue to write the letter using informal but affectionate language. Address your girlfriend throughout the letter to make it more touching, but keep the letter flirtatious.

Be honest and respectful, but not too heavy. You will have plenty of time to show your feelings, so don't scare off your new girlfriend with an early marriage proposal or obsessive love declarations.

Conclude the letter and sign it. End it with a thoughtful sentiment such as "You make me feel really good, and I can't get enough of your hugs and kisses." Then add, "Lots of snuggles, from Ben."