Keeping a spiritual journal is a simple yet powerful technique to help you record your own spiritual experiences as you study LDS scriptures. All you need is a notebook of any type and size. You can copy touching passages, note inspirational thoughts, and many other things. Just make sure not to lose your notebook. If it's small enough you could tuck it in a case for carrying your LDS scriptures.
You can also use your patriarchal blessing when studying LDS scriptures and make notes in your spiritual journal about it. A patriarchal blessing is your own personal scriptures from the Lord, like a chapter written just for you and it can be a very powerful resource if you study it often. You can study it word by word, phrase by phrase, or paragraph by paragraph by looking up topics in the Study Helps (See Technique #8). I have a small, laminated copy of mine that fits in my scriptures so I always know where it's at. If you'd like to mark up your Patriarchal Blessing make sure you use a copy and not the original.