For a start try to rhyme any words that come to mind. You can enable any bit or, at worst, the metronome, the main thing - not to hurry. Fast reading is not so easy, everything comes with experience.
When the rhyme will not be a problem, try to come up with lyrics with meaning. And, of course, do not forget about bit.
Gradually try to combine tact, and sense and rhyme together.
Speaking of rhymes. MC for beginners to practice better on simple rhymes, when in the string there is only one rhyming word, and it is worth it in the end of the row. Such rhymes are and freestylers, as there is always time to think. The more you practice, the harder rhymes. In order to make the texts varied, MC use an internal rhyme, i.e. the rhyme words are within the string. The use of such schemes adds to the texts of imagery and energy. As you improve, begin to experiment with complex rhyme they rhyme more than one syllable. To make these rhymes are harder, but these rhymes bring to the text diversity and improve the quality of the text.