1.  Follow this golden rule: never allow yourself to go two days without practising unless you're ill or on holiday. (Though we recommend bringing a guitar on holiday!) No practice = no chance of improvement. If you follow this one rule, at the very worst you'll have practised about half the days of the year, which isn't too shabby. There is no better practice tip than the one that will get your doing it lots. This is that tip.
   Your secret weapon to maintaining this golden rule though is the "one-minute practice session", for those days when you're frantically busy and/or exhausted. That little nugget of practice is a great deal better than nothing, if only because it helps to maintain the golden rule. Besides, you might find that the one minute can easily turn into two, five, ten, thirty...
   
   
2.  Make a concrete distinction in your mind between practising and playing. Guitar practice could be regarded as the endeavour to eliminate problems from your playing. For this you need to know exactly what those problems are, then target and attack them persistently and cunningly. The more ways you can invent to practice something, the better. Whereas playing is essentially going over things you can already do. Playing is fun, and you should do it. It is in fact the point of learning the guitar in the first place. But it's not the same as practice. Be clear about which you're doing at any moment of making noise on the guitar, they shouldn't sound the
   same. Your progress stops when you're only playing, and the fun stops when you're only practising.
   
   
3. What feels "right" probably isn't - unless it consistently sounds right. That feeling of comfort and "rightness" in playing is a product of familiarity and nothing else, it has no necessary relationship with good technique. So if you feel as though you're not progressing, it's very probable that you've become familiar with poor technique and don't truly want to abandon it. But it helps to resolve in advance to be ready do so without hesitation if your teacher is recommending a different technique than the one you're accustomed to. Even if the new way might seem extremely counterintuitive, uncomfortable and seemingly ineffective at first. Remember that barre chords fall into that category for a beginner, but of course that strife doesn't arise from any problem with barre chord playing advice. Note that the beginner does not improve at barre chords by avoiding playing them. So likewise, be humble, consider yourself a beginner in respect to the technique, and expect a similar prolonged struggle. This struggle is borne purely of unfamiliarity, which conversely is entirely independent from "wrongness". People get stuck in ruts precisely because of this imagined association between comfort and effectiveness, and its reciprocal: discomfort and ineffectiveness.

There are only facetious answers to this question, I'm afraid. Which is a shame because I agree that it's an important one. But consider the problem of answering it. People vary: in their abilities, their definition of what is good, and their perceptions of their ability. Furthermore, practice is variable between people: its frequency, duration, and effectiveness. So, we've decided that the best thing to do is to give up answering this. Instead, we recommend that people track and review their progress regularly to evaluate whether or not they are content with it. How to do this well is something we do have a good answer for.

Firstly, at Guitar To Life, each guitar lesson begins with 10% of theory. Theory progress is tracked by the guitar teacher with a checklist that is available for students to view whenever they choose. Another way is to create your own realistic, short-term benchmarks. We find that no one knows what constitutes an achievement better than the individual striving for it. We provide the means for you to view this alongside all other GTL content. But perhaps the most convincing method to track progress is to record your playing regularly, and review those recordings at the end of each quarter. After a while, out of this material you can make a compilation video of your progress, which can make for extremely satisfying viewing.