To achieve a great result, the effort must be great too. No one really can come up with a trick that will minimize the importance of effort, but what everyone can do is maximize the result of the given effort. How it works then?
Well, I cannot simply give a single answer to that question, because a single answer/method won't work for all of us! But yes we can maximize the result of the effort by simply evaluating our current level and to explore the next level.
Current level is termed to a situation where you have a fair control over the techniques that you already have learnt but you have to work on a regular basis to get more fluency. Next level is termed to a situation where you will enter as a newbie and have no control whatsoever.
So how to work in an existing level? Why don't you design a practice session for yourself? Simply ask yourself what are the primary problems that you face while playing a phrase or a part of a song followed by a particular technique. Let's say that you have problems with sweep picking.
First of all, let's draw a diagram of an arpeggio over a piece of paper [I assume that you already know what arpeggio is] and sort out the notes. Next comes is the How to do it. Remember that there are always tons of how to but really quite a few to avoid! So if you can figure out the what to avoid, then you have understood the principles of the technique and can build up a better technique that totally suits you! Earlier, we took sweep picking as a problem; let's see what should be avoided in a sweep picked arpeggio.
So these are the common what to avoid stuffs. If you have already understood the principles then by now I assume you have understood that hands synchronization is a very important part while using sweep picking. So now you have a grip on your weaknesses and you really can build up a technique that works better for you. Above examples are just assumed as common problems. You might find out more/less, that's why I have said that, a single answer/method wont for all of us.
I have discussed about evaluating ourselves and designing a practice session. I mainly focused on building better techniques by simply locating the things that has to be avoided.
Now I will focus on TIME. Great musicians have worked way longer in time, but let me tell you what, it's not only the TIME that made them a great one, and it's the balance and stable relationship between time and effort.
2 hours of balanced practice sessions and concentrated effort will work far better than working 10 hours a day without any balanced routine. When you design your practice sessions keep in mind to divide your time as widely as possible so that you develop in more areas at a regular frame.
So how to create a stable relationship between time and effort? Simple. Don't overwhelm yourself with tons of exercises, chose what you are not familiar with and find out the things that has to be avoided before even developing a technique.
Bridge is something that I use to demonstrate that how someone can create stable relationship between time and effort. Bridge is the last thing and the most important one; can you guess that what is this bridge? CONSISTENCY. Draw this word in your mind; you will see the results by yourself!