Meditation - how to practice it?

OP: Is it more important to develop one's own meditation skills or follow a prescribed method of a teacher?

Both. You should follow a teacher, who teaches not just meditation, but also the rest of the Noble Eightfold Path. The teachings of the Buddha are called the dhamma.

The teacher of the dhamma should have the following qualifications according to the Udayi Sutta:

"The Dhamma should be taught with the thought, 'I will speak step-by-step.' "The Dhamma should be taught with the thought, 'I will speak explaining the sequence [of cause & effect].' "The Dhamma should be taught with the thought, 'I will speak out of compassion.' "The Dhamma should be taught with the thought, 'I will speak not for the purpose of material reward.' "The Dhamma should be taught with the thought, 'I will speak without hurting myself or others. "It's not easy to teach the Dhamma to others, Ananda. The Dhamma should be taught to others only when these five qualities are established within the person teaching."

While a good living teacher nearby is preferable, it is also OK to use the Buddha's teachings (the dhamma) as a guide through the scriptures and other books and commentaries, or Youtube videos of teachers far away.

After all, in the Maha-parinibbana Sutta, the Buddha said:

Then the Blessed One said to Ven. Ananda, "Now, if it occurs to any of you — 'The teaching has lost its authority; we are without a Teacher' — do not view it in that way. Whatever Dhamma & Vinaya I have pointed out & formulated for you, that will be your Teacher when I am gone.

This means that even the dhamma by itself is good enough to be a teacher.

OP: After all I think the Buddha worked it out for himself.

That's not true. As mentioned by chang zhao, the Buddha did learn from other teachers, as stated in the Ariyapariyesana Sutta, but it wasn't good enough. But luckily for us, the dhamma can be our teacher.

OP: And I have noticed in my own practise that following someone else's method can be confusing, if I don't understand properly what they teach.

This is where having a good living teacher nearby is helpful and you must ask them questions.

In the Alagaddupama Sutta, the Buddha says:

"Therefore, monks, when you understand the meaning of any statement of mine, that is how you should remember it. But when you don't understand the meaning of any statement of mine, then right there you should cross-question me or the experienced monks.

So, although the dhamma is our teacher, but a living teacher (who is experienced) would be able to answer questions. The earlier part of the sutta explains why it is good to gain a correct understanding and grasp of the teachings.

OP: Is discovering it for yourself, such as meditation, the best way?

You can use the dhamma or the teachings, as a guide, and then you can discover for yourself. If you explore on your own without leveraging on the teachings, you might not make much progress. But using the teachings as a guide, you can deepen your knowledge, enhance your practice and make more progress. If possible, get a teacher.

According to the Attadiipaa Sutta:

"Monks, be islands unto yourselves, be your own refuge, having no other; let the Dhamma be an island and a refuge to you, having no other. Those who are islands unto themselves... should investigate to the very heart of things: 'What is the source of sorrow, lamentation, pain, grief and despair? How do they arise?' [What is their origin?]

Both. While it's pretty much impossible to make real progress in meditation on your own, under the guidance of any good teacher, you are still expected to figure things out for yourself. I know this seems contradictory, but a meditation master can only guide your progress. It's absolutely impossible for them to get into your head and show you how to practice. Think of sitting as a skill like wood working. While the master carpenter can give you instructions on how to cut a board, only through your own efforts and experience will you understand how much pressure to use on different wood types, how to work the grain to your advantage, etc. Likewise, on the cushion, while your teacher will tell you to watch your breath, it's up to you to figure out how firmly to apply your attention, where the best anchor point is for your mind, how much to relax, and how to use your posture to your advantage. Like any skill, mastery only comes through countless hours, many questions, ample feedback, and innumerable breaths.

or follow a prescribed method of a teacher?

In Buddhism, when we are beginners, we generally follow methods of a teacher because generally the method of a teacher has a goal, has structure and can bring some preliminary results that give a taste of the goal.

After all I think the Buddha worked it out for himself.

The Buddha did work it out for himself; which is why he is so esteemed because working it out for yourself is very difficult, close to impossible, which is why it took the Buddha six years to work it out.

But you seem to have overlooked the fact that the Buddha did not actually know what he was trying to work out; apart from looking for real peace. He was searching or groping in the dark.

And I have noticed in my own practise

What practice? What exactly is your own practise? This has not been made clear.

that following someone else's method can be confusing, if I don't understand properly what they teach.

An effort is made to work out what they teach; such as asking questions about what they teach.

Is discovering it for yourself, such as meditation, the best way?

Discovering what for yourself? Respectfully, you haven't mentioned what you are trying to discover.