こんにちは。
kjmdさんの考える迫力ある絵というのは良く分からないのですが、自分なりに描かせていただきました。

気を付けた点としては、
・顎の下・襟足・耳の穴・髪の影など暗くなる部分はベタやカケアミで暗くする。
・グラブルとBL作家さんの絵を参考にする。
・完全再現Gペンで描く
です。

なんにせよ上手くならないと迫力は出ないと思うので、漫画制作と並行して絵の勉強もされると良いでしょう。
絵が上手くなるコツは、上手い人の絵を真似ることです。
kjmdさんがヴァンパイアの末裔で、この後何千年も生きるなら、試行錯誤しながら自分の絵を追求してもいいですが、そうでないなら素直に上手い人をお手本にして賢く上手くなりましょう。

ご参考になれば幸いです。

nice to meet you.
I'm sorry for being anonymous, but thank you in advance.

According to a book, university professors plan and teach lectures with the goal of fostering researchers in mind (despite the fact that most of the students do not stay at the university and find employment at companies).
If you seek advice from a commercial cartoonist, you will probably be in the same position, so you will be able to find out the problems and get pointed out under the assumption that you are an aspiring commercial cartoonist and his work.
Even if you show it to a commercial magazine editor, you will probably think about whether it is worthy of publication from the viewpoint of commercial profitability, and what kind of transformation is desirable for maximizing profits.
(Since I am an outsider, he cannot understand the effectiveness and appropriateness of it. However, if you intend to focus on non-commercial activities, the necessity and value of tampering with the design may be unclear.)

I thought it would be more constructive for you to present a prototype image as a result of your efforts to improve if you yourself feel uncomfortable or uncomfortable, not because someone told you to.
The following is a generalization because there are no specific images of the trial production.

The drawing tool for fine lines is similar to drawing with a drafting fountain pen (also called Rotring from the name of a representative manufacturer) in the style of our predecessors.
I think that a mechanical fountain pen is a tool that allows you to get a unique line with a mechanical impression by scraping off the information attached to the drawn line.
IRI and NUKI, which are repeatedly called out in manga textbooks, and the momentum of the lines themselves are, so to speak, a kind of "incidental information", so naturally there is no "that" in the drawing style of a drafting fountain pen.
Therefore, in order to form power and momentum with the same tool, I think it would be a good idea to overlap lines so that the whole of multiple lines suggests momentum.

Or better yet, I think it would be effective to use another tool.
In a digital environment, if you use a pen tablet that supports pen pressure input, there seems to be drawing software that supports pseudo-analog lines.
Or, although it may be old-fashioned now, I think it would be effective to draw with a G-pen and ink.
(A long time ago, there were some commercial manga artists on the internet who clearly stated that if they got used to it, it would be faster to draw the main lines using analogue;
I haven't researched it recently, so I don't know.)
Also, pencils are art materials that require training, but in Japan, many schools use pencils as writing instruments, so many people are familiar with them.
Pencils are probably not suitable for the purpose of applying for the Rookie of the Year award for manga, but they can be said to have a high potential for amateur use.

In the lines drawn with them, the accompanying information is difficult to erase, and the speed of drawing remains on the line as momentum, and it comes to life.
If you can make full use of them, it may be an effective means for depicting scenes where you want to create a powerful effect.

Even if his clumsiness becomes apparent temporarily by trying to draw with other tools, it can be said that he has made the problem manifest in a state where it cannot be hidden.

What would happen if the problems that were hidden and escaped until now were revealed in detail and overcome with effort?

Isn't it possible to make the lines drawn in the original style especially beautiful?

If you take it that way, this predicament might even be called a blessing that invites you to a bright future rather than an evil.

I look forward to your fulfilling expression activities and success.