What happens with newly solo'ed pilots is that your stick control, usually trying to compensate for every single movement the plane makes, takes it's toll on batteries because the servo's are always, constantly, working to match your inputs. This is perfectly normal, and you will usually 'grow' out of that as you gain experience and confidence.

What I was told one day, by my instructor, was to just leave the sticks alone and let the plane fly from left to right or right to left without making any minor.... MINOR... adjustments. Of course, serious change requirements must be dealth with on the spot, (for instance, if it starts a serious dive, don't leave it, correct it..., or a serious bank to the left.. fix it). But just leave the sticks alone for a few seconds and watch the plane. What will happen, in most cases, is that it will almost self correct without the need for your input from the transmitter. Eventually, you will get the feeling and you will see what little input it actually takes to fly straight and level.

This is, of course, after you take off and do your basic trim adjustments for 'hands off' straight and level flight.. at that throttle setting. Remember, a change in throttle setting will change your trim. More throttle and you will climb. Less and you will descend. So, set the throttle, say at 1/2 to 3/4, whatever your normal airspeed is for flight, trim it out, then just take your fingers off of the sticks and see if it flys straight and level. If so, then you're all set to do the test above. If not, trim it till it is ready, then try the test above.

Servo's will definitely drain the batteries in short order if you are constantly on them. The more experience and confidence you get, the longer the batteries will last. But, don't get rid of that voltmeter... Oh, not just a voltmeter, but a loading voltmeter or an expanded scale volt meter. A regular voltmeter will tell you 'Yup, there's voltage there' but a loaded or an expanded voltmeter will tell you how the battery reacts under the standard load of a receiver and servo's. If analog, and it's in the green, you're all set. If it's not in the green, then do yourself a favor and hit it with a field charger (sirius field charger is a great choice, by the way, as are Tritons, ICE, and many others, depending on your needs). Charge the battery. Don't take a chance. More crashes have happened by marginal batteries where the pilot says, "Well, I have one more flight in that battery".

By the way, congrats on your solo. Enjoy the hobby as we all do!!

DS.