I've been ridiculously busy since school started; golf, football, regular classes, girlfriend, friends, etc. I tried to keep fitting in guitar practice but with only 30-45 minutes a day I noticed absolutely no improvements after a month, whereas my first month I made a jump from not being able to even form a chord to being able to freely switch chords, make chords, find notes, find scales, improvise, etc.

So, I'm wondering, what kind of practice schedule should I use, if there's one possible, so that I can keep improving using 30-45 minutes a day?

I'm already to actually play it but it's hard for me to keep practicing if I can't work towards my goal of actually being able to play stuff like Bodhisattva (Steely Dan) solos and metal solos in general and instead have to keep playing **** like Comfortably Numb and Stairway to Heaven that I couldn't care less about being able to play I'm just going to end up giving up. Songs to try to practice, exercises, riffs, whatever you guys can suggest. Plzthx
30-45 minutes a day is fine. If you practice the same amount each day, your skill level will always grow proportionally. However, there is not always a noticeable difference. When you start off, you notice your progression much more easily. But as you get more and more advanced, it's more difficult to notice. But don't worry; you're still improving. Although you have a decent daily practice time, try to focus on technique during that time. Don't spend the whole time screwing around and playing whatever. Practice certain material and work on improving. You will notice a change in time.

Im not sure ifs this way for others but my improvements always seem to come in big bursts. Practice practice practice practice not very much noticeable improvement then all the sudden one day (usually after a day or two off) BAM fingers start flying

What Aero said is also very important. Make sure you are practicing things that you cant do, it doesnt do much good to sit around and play a bunch of riffs you already know. 45 minutes can be plenty of time if you do this
I believe it was rumored that Paul Waggoner of Between the Buried and Me fame used to practice for roughly 30 minutes to an hour everyday. His skill speaks for itself.

If you've ever sat down to play with a regimented practice schedule, you would know that such an amount of time is more than enough to isolate techniques and practice them with efficiency in mind. I personally do no more than an hour of practice each day (occasionally I'll play for 4 hours, this is not necessary) and my technique is above average...I'm also modest, too.
Quote by Junior#1
Gilbert mutes with both hands. Palm muting and left hand muting. As for anchoring, he doesn't. He doesn't need to. After all, he's the creator of life, the universe, and everything.
Its not about schedule man, its about feeling. Practice with your heart even if its 10, 20, or 600 minutes a day. That will make you a better musician.
Sit down each day and set a goal you can complete in your time.

10 minutes - learn a single sequence.
20 minutes - use a new chord voicing.
30 minutes - learn a simple song.

Etc etc.

Just make sure you achieve something every time you sit down and all your time is well spent, fun and moves you towards your goals.
To make it easier to notice progress, record yourself playing every now and then so you can listen in the future and realize how much better you've become. It's hard to recognize progress from day to day and sometime you feel like you've taken a step backwards, but if you are consistent in your practice you'll make progress.
Something I did when I was building speed was pick different scale patterns and play one each days, and I would keep a log of how fast I could go up and down the scale, how fast I could do it playing it 3 notes at a time ( for exampe in the C scale:C D E -D E F- E F G- F G A etc) and then 4 notes at a time ( C D E F- D E F G ....) and I noticed how I didnt necesarily increase my speed every day, even some days I played slower than others, but as time went by speed slowly increased, sometimes gradually and every once ina while in bursts
I think 30-45 minutes is a bit limiting, but like Freepower said, if you are focused and work on small achievable goals, you can still make progress.
I obviously don't know your exact situation, but if you are really serious about this, I'd try to find a way to make a bit more time. Sure you might have to sacrifice a couple of things, but in the end it comes down to choices - you have to decide which you want more. It works the other way around as well - I would love to play 4-5 hours/day, but it's important for me to make time for my family, so I limit it to 2 hours most nights.