The practice of concentration on a single subject (or the use of one technique) is the best way to prevent the obstacles and their accompaniments.
To prevent or deal with these nine obstacles and their four consequences, the recommendation is to make the mind one-pointed, training it how to focus on a single principle or object.
The antidote to these obstacles is maintaining a regular practice and sticking to it, through good times and bad. Sounds simple, but sometimes just showing up for our practice is the difficult bit.
Patanjali is saying that the method or technique of meditation is not important, rather that we persevere. Some days, the practice will be easy and we will feel pleased. Other days, it will be tough or things will appear to prevent us from practising at all. Showing up is key.
In the next few sutras, Patanjali outlines some different techniques of meditation.