You don't need an array of fancy aids to fix things - use your golf bag.
For me, the swing plane is golf's equivalent to football's offside rule. Everyone talks about the effects of it, has an opinion on it, but not everyone is exactly comfortable in what 'it' is.
You produce your optimal swing plane angle as you set-up to the golf ball. It is an imaginary line that starts at the clubhead, travels up the shaft and extends out through the grip behind you.
As you can imagine, this line is influenced by individual characteristics such as your height, build, posture, technical mobility and the length of the club in play.
The objective, however, remains the same; the closer you can get to adhering to the line throughout your swing, the more powerful ,consistent and accurate your contact with the ball will be.
The concept of the swing plane is relatively simple. The problem arises ,however, as it can only really be viewed from a position behind the golfer.
The technology in cameras and smartphones these days is great - the problem is you still need a second person to stand behind you.
So what do you do when you're on your own? Answer: use your golf bag. Stand bags can be positioned anywhere from 90 to a 45 degree angle. Providing a wide range of options for individual set-up styles.
If the club shaft consistently mirrors your golf bag's angle throughout the movement, great. If it is more vertical or more horizontal, your swing is not as efficient as it could be.
AND ANOTHER THING...
Test your balance by holding your follow-through position for a couple of seconds. It is a position many amateurs feel is unimportant as they can no longer influence the ball.
But by holding your follow-through, not only will you recognise balance problems in your swing, but it will actively encourage stability throughout it.