Well...
1 - Don't be intimidated by people when they say 'I practised for 20,000,000 hours today' - If you practice well, it will show in your playing, you wont need to tell people you have.
2 - Split your practice up. If your looking at 45 mins, I would do something like this
5 mins - Warm up - Big Strokes - Free stroke (look it up on youtube)
10 mins - Sticking Patterns or rudiments, increase tempo by 5 bpm every 2 mins
10 mins - Hand and foot coordination e.g. working with doubles between hands and feet round the kit keeping quarters on hi-hat with left foot. Increase tempo by 5 bpm every 2 mins
10 mins - Groove exercises - Work on your groove playing - Time Functioning Patterns by Gary Chaffee is a great book
10 Mins - Chart Reading/Styles/Play along. Use this time to work on sight reading, learning some new styles like Latin Styles or Jazz or just play along with a song
Always stick to the times you've stated. If you run over, just stop. Pick it up next time
3 - ALWAYS practice with a metronome - if you don't have one, get one
4 - Keep a practice diary. Take off from where you left off, so if you finished at 85 bpm last time, try starting at 80 bpm next time, increasing your start position by 5 bpm (or where you're comfortable) each time. Not only will keeping track improve your practice, but it will also teach you not to practice the same thing.
5 - Get some good Literature. I have lots of drumming books. I take little snippets from each. Not only does this unlock your potential, but it also gives you an insight into the different ways of playing. If you struggle with the reading, slow it down and work it out, or get your teacher to help
6 - Be patient and keep it up. 45 mins a day is better than nothing and remember, everyone started somewhere.
Finally - Don't let people get to you. There will be players who will chop all over and make you feel like an ant in drumming, but remember, they play to satisfy their ego, you should play to make a difference and make some damn good music!
Peace