WRiting to beats will help you develop a better rhyme scheme, itll take awhile but after a lil youll be able to count the bars on the beat, so you can match up your bars with them.

But after awhile youll be able to flow off your head with out any beat and still hit the same ammount of syllables, first try just writing with ten, then once you can always hit ten with out a beat, or thinking about hiting ten, work on another number.