Can you do it when it really matters?
To putt well you must first learn to putt straight. This requires an ability to square the blade of your putter to your target at the moment of contact with the ball.
To improve your putting you need to practise.
However, rather than just knocking balls around the practice putting green, you should divide up your practice so that you spend time on each of the different putting skills.
To putt well you must first learn to putt straight. If you can't hit your ball in a straight line over a short distance of, say, three feet on a perfectly true and level surface, you will have difficulty in becoming a good putter.
In reality most of the putts you will experience on the golf course will not be on a perfectly true and level surface for they will have some slope to them.
This means for putts off the Fall Line picking an aimpoint (target) located away from the centre of the hole. You must develop the necessary skill to putt at this aimpoint so that your ball consistently starts off towards it in a straight line.
So how do you practise a straight putt? You can only do this on a surface that is true and level so the direction your ball travels is entirely the result of your effort.
Unfortunately most practice putting greens are not ideal. This is because the feedback you receive may not be accurate. The best practice is achieved when you can eliminate all outside influences such as unevenness of the surface, direction of grain and so on.
Setting aside for the moment the technique of aiming which is another important skill in putting, a straight putt is the result of your putter blade striking the ball squarely so that it rolls precisely end-over-end.
A simple way to test the roll of your ball is to draw a line around its circumference, place your putterface perpendicular to this line and then watch the line on the rolling ball.
If you have made poor contact, the line will wobble indicating that your putt was off-line rather than straight.
There are a number of putting aids that can help you to practise squaring your putterface at impact - the essence of perfecting a straight putt. They vary from Tru-Putt Putting Tube by Dave Pelz to The Rail by Harold Swash.
Other similar putting aids are the Putting Stick and Checker Balls.
In a sense if you hit any putt on a true and level surface it will travel from Point A to Point B in a straight line. However, Point B may not be your aimpoint.
You want your ball to travel to your aimpoint in a straight line and this requires the skill of squaring your putterface at the precise moment it comes in contact with the ball.
My preference in practising a straight putt is the Rail as it can simulate putting under pressure. The aim is to roll your ball as many consecutive times as you can from one end of the Rail to the other without it coming off the narrow track.
It's fun, it can be used both outdoors and indoors, and most importantly it is good way to practise how to putt straight.