Can I strengthen my voice?

When you speak try to... taKe... a... slighT... pauSe... betweeN... eaCH... worD... anD... enunciaTe... the... lasT... consonanT... oF... eaCH... worD. It will sound a bit weird, but start speaking out loud to yourself this way, and then add bits and pieces of it to your social speaking. It forces you to speak slower and with more opportunity for emphasis. Remembertoneverspeakinamonotonevoice. This comes across as mumbling even if you have good diction. Again, as an exercise, speak an entire, long sentence while breathing in. Then do the same while breathing out. Vocal projection benefits from knowing which parts of a sentence are spoken on the intake and/or outtake of breath. Read out loud to yourself, at least, if not others. This will bring make you aware of what you need to work on. ANYBODY can condition their voice to be what they want it to be. It is your audible posture and the benefits of pursuing it are great.

Yawn, and pay attention to the way the back of your throat opens up. Try to do this somewhat when you talk. It will take a tiny bit of practice to sound normal (at first you'll sound like Kermit), but you'll get it. Also, take deeper breaths (not necessarily longer, just control the breathing with your diaphragm and feel the air pull down further towards your gut). Support your voice with your diaphragm. Practice taking deep breaths and letting them out slowly and steadily (see how long you can exhale in one steady stream with no faltering, wavering, or changes in force/speed). As you increase your time, you are learning to control and support your diaphragm better. If you've ever played a woodwind or brass instrument, or swam/swum/swimmed competitively, you might know how this feels. If not, find someone you know who has singing experience or plays a wind instrument, and ask them to teach you how to breathe. Someone who does a lot of shouting in the military will probably have good advice. (I am not a speech therapist)

I asked a http://ask.metafilter.com/14967/Voice-Care 4 or 5 years ago and down towards the middle are some links to breathing exercises and other info that might help. I'm in a similar field, although I no longer have to do as much non-stop talking as I once did. I've been doing a lot of instructional videos recently and these have actually helped my voice out. The main thing I took away from that is to try to breathe deeply and relax. (Easier said than done, of course.) It's amazing how much tension one holds in the body unconsciously and there's something about talking in front of people that seems to ratchet this up.

I found that after I did simple vocal warmups targeted towards singing, my speaking voice would naturally fall into a lower, more relaxed register for the rest of the day. You could find some that you like, and do them in the morning.

my voice is not one that can project and command a room like some of my colleagues This statement doesn't make any sense; anyone can train their voice to project and command. What is really going on here is that you may be shy or culturally conditioned not to make a lot of noise with your voice.

Make sure you're in decent physical shape, and that you carry your body with a good posture (eg stand tall, shoulders back), and that you can allow your body to move somewhat freely when you speak. This will support good breathing that comes from lower at your diaphragm than from say at your throat, and give you better breath support and control to back your voice.