Practising yoga by yourself is the way forwards. This is when our practice shifts from being somebody else's (that guided by the teacher), to our own, guided by ourselves. Pretty much everyone needs a teacher as well , but with practice we can be taught by the 'inner teacher' much of the time.
The 'inner teacher' is not some mysterious being, it is a faculty we all have that requires we learn to trust ourselves and our felt sense of what we are doing whether in asana (posture) practice, meditation or indeed in how we lead our lives. When we are guided from the inside, we also learn what type of practice we need at any particular time.
As a general guideline to practising the postures by yourself, I would suggest that when you start any pose:
- Do less than you can.
- Relax and feel what you are doing with respect to grounding yourself and breathing.
- Listen to the feedback messages from your body and only then move deeper into the position if that feels right.
For formal sitting meditation, some formal instruction would be wise to start, though there is no harm to experiment by just sitting still for 5 or 10 minutes and closing your eyes.
When we start to practice by ourselves, 10 minutes a day will make a difference. It is achievable as we can all find 10 minutes if we want to. Once we start we may find ourselves spending longer. The most important thing is to roll out the mat, or sit on the cushion, and begin.
For asana (posture) practice, roll out your mat and start in whatever way is familiar to you from your class and then try to work from your body memory to proceed from there. You may be pleasantly surprised what you can remember. If you can't remember anything, or enough, try paying close attention in your classes to the sequencing of poses and try again.
Good luck - and remember - just start.