The only way to advance in aikido is through regular and continued practice. Attendance is not mandatory, but keep in mind that if you want to advance in aikido you need to practice at least three times a week. In addition, as aikido is a way of cultivating self-discipline, self-discipline begins with regular attendance. The more you practice, the better. In a few years it will be obvious how much time, will and effort you put into your practice. There is no way to be good at the skill if you do not practice. There are no overnight results - be good in any martial art means a great commitment.
Aikido is physical training, but in the first place, it is training of the mind and spirit. Aikido is not about winning someone else, but the victory over yourself. It is about creating character and personality. You should always practice with pleasure, or at least try so. To overcome the frustration is also a part of training.
Although aikido is best learned with a partner, there are many ways of performing solo training in aikido. You do not need a partner for some exercises with jo and boken, such as katas for example. Practicing with an imaginary partner, the so-called "shadow" techniques, is another way - just imagine that you have a partner and perform movements like doing techniques on him. In the same way you can practice to be uke - move as if someone is really doing techniques on you. Even if you just perform the aikido techniques in your mind it can serve as an effective form of solo training.