Have your guitar close to hand in your bedroom because it encourages practise. Preferably keep it plugged in and within arms reach, so you just pick up, flick a few switches, and play.
Have a comfortable practise environment. Keep your wrist, hand and back posture correct and you will be able to practise for longer.
Keeping your wrists relaxed helps stamina and speed and will help prevent cramp.
Keep trying to push yourself mentally and physically but do not strain your wrists too much. Repetitive strain injury is possible from playing guitar and it can interfere with practise, and it hurts.
Take regular breaks when you practise (around 5 minutes every half an hour). This enables you to mentally record progress and music you have made, reflecting on what you have done also gives your wrists a break.
Don't play the same material every day other wise you will develop a "comfort zone" and you will be useless at all music outside that zone.
Don't be afraid to try out a capo or different tunings. Sometimes new creative ideas come from playing in different tunings. Also, alternate tunings allow you to play in a different key without changing your position on the fretboard.
Warm-ups are essential. They help you play for longer and keep you wrists healthy. Jumping straight into fast and difficult music can be damaging to your wrist and your confidence. Don't forget, even professional guitarists can sound terrible without a proper warm up. Or if they haven't played in a while.
Using scales as exercises naturally provides a variety of finger combinations to practise. Try ascending the C major scale on one string by playing three notes, starting on the root note, then three notes starting on the on the second note and so on.
Buy a metronome and use it regularly. Use it to warm-up with scales.