Beginners want immediate results and will tend to work out things their own way. This is the downfall of many beginning student.
Cultivate good habits. Practice regularly with patience. The fundamentals, such as drawing different strokes well, must be mastered first. The more regular your practice, the better your results will be.
When drawing, set aside time for just that. Do not be distracted by anything else. Ideally you should have a place away from distractions to use for a length of time. Do not overdue it though. One hour a day is sufficient practice, without becoming a task.
Choose models that are simple. When starting out, select subjects that are plain with no detail. Practice these, under proper drawing guidelines, before moving on to complicated subjects.
Manuals and rules of drawing will not produce art genius, but you must learn them first before you can even begin working on your masterpiece. Find and follow a reputable course in a book or online.
Follow beginning steps in any course of drawing carefully. Do not skip or jump ahead in order to get fast results.
Stay strictly within the rules and fundamentals of drawing until you have mastered them. Experiment in your own way only after the basics are mastered.
Guidance is needed. You can not simply start drawing and expect to learn how to draw well. If you picked up a violin and simply started to play you would become a violinist?
Trying to draw complicated scenes with much detail will lead to frustration and disappointment. Developing basic drawing techniques with very simple subjects first gives a solid foundation to build on. Success builds upon success.
Focus on drawing one single object correctly, as opposed to many objects arranged in a scene. You must be able to draw the individual object before you can draw many objects in a scene. This may seem obvious when reading it stated plainly here, but when drawing one often forgings such simple rules in the rush to produce wonderful drawings with little practice or knowledge.
Repeat the basics, practice fundamental strokes, lines and perspectives. Practice every day what you have learned. When the basics are mastered, combine them to produce more detailed drawings.