Just start, without thinking!
Here are some advices that will allow you to draw manga drawings but also any other kind of drawings:
1) First of all, don't be afraid, just start, without thinking, you don't risk anything, it's a draft! It is better to start and make mistakes than to know exactly what to do.
2) Never start with the details (fabric folds, eyes, shading, nails, toes, etc...). First, always draw the outlines of objects, characters, just making circles, squares, simple shapes. This allows you to see if everything is well proportioned and if things are in the right place on the sheet.
Example: If you drew a head that was too big and too high on the paper and you wanted to draw the hair as well, you'll be glad you didn't take twenty minutes to do the eyes, the eyelashes and the highlights when you have to erase to put the head back down.
3) From time to time, take the sheet and look at it from the front with more distance to see if everything is as you want it.
Example: Unless you have a tilted drawing table, you will be looking at your drawing from below and your view will distort the drawing slightly. Taking a step back and looking at the big picture can also help you realize some of the problems that you might not have seen if you were too focused on one part of the drawing.
4) Make lots of lines and lots of tests, it's a drafting sheet, don't be afraid to make a line in the wrong place, if it's wrong, redo it immediately without erasing. It is only at the end that you will pass the best lines in darker.
5) If there are elements (fabric, water, ...etc) that cover other elements, you must first draw what is underneath without anything else, then add what covers.
Example: If you want to dress the characters, you must first draw them naked. That's right! The fabric follows the shapes of the body so it is important to know what those shapes are and especially, the fabric is far from the body, so you will have to have the body naked before you can put the fabric on it and move it away from the body.
6) To ink, go over the pencil lines with a pen and ink or a black pen, start with the right side of the drawing if you are left-handed and start with the left side of the drawing if you are right-handed
Example: If you start on the left side of the drawing when you are left-handed, your hand will go over the ink lines and you will mess up your paper and damage your lines.
7) Choose the liner that suits you best. Start with the thin lines, then finish with the lines you want to thicken with thicker liner.
8) When inking, you need to practice a good wrist movement. Your strokes must be smooth and accurate. Don't hesitate to move your paper so that you can make a nice gesture in the right direction to make a nice line.
9) Don't be afraid, have fun, you can always catch a line even if it is wrong. You can double the lines with two thin strokes and then fill in to make the thickness you want, thicker in the middle of the line and thinner at the end of the line.
10) If you want to progress, don't draw characters from the front anymore, but invent new points of view, from three quarters, from above, from far away, etc... this will make your drawings much cooler.
11) For coloring: Color in the right direction, in the direction of the textures you draw.
Example: If you color hair, color in the direction of the hair, sometimes it even adds texture.
12) Always test your colors on a draft sheet before applying them to your drawing.
13) Start with the lightest color and work your way up to darker colors for shading.
14) Don't go all the way to the black line, stop a little before that and leave some small gaps that you can fill in later. If you go all the way to the line, you risk going over.
If you want to take drawing classes, don't hesitate to sign up for the comic book/manga drawing classes to learn how to draw your favorite characters and perfect your drawing techniques, in Lausanne, Morges, Montreux, Bienne and Delémont. And to deepen your knowledge even more, you can take part in the comic/manga drawing summer camps that take place all over French-speaking Switzerland during the school vacations!
Discover also: How to draw a hand, How to draw feet, How to draw a nose, How to draw a body, How to create a comic/manga character and many other articles.