First off, don't sweat it. Your results sound exactly like mine when I started AG. I was also worried about sparge speed and a lot of other things back then. I have found that sparge speed is a very minor factor in my efficiency if at all. There is a good sticky on this already. The information there is great and I suggest you read it:
https://www.homebrewtalk.com/f36/maximizing-efficiency-when-batch-sparging-77125/
A few minor tweaks helped me go from 50% to 72-74% efficiency (where I'm currently at.)
Measure water volumes accurately
When I first started AG I didn't have a way to measure more than 2 quarts at a time. I guessed at water volumes in the tun and kettle. Turns out I was using way too much water, thus diluting my wort. My efficiency was better than I thought, I was just making a bunch of weak beer.
Get a good grind on your grain
Most folks will say this is _the_ most important factor when improving efficiency. I found that accurately measuring my water helped more, but that's probably because the grind from my LHBS wasn't too bad to begin with. I did end up buying my own mill and get a good -- but more important: consistent -- crush now.
Sparge in two batches
I believe Bobby_M has a post on here about batch sparging in 2 batches. Hopefully someone else can help with a link. The basic point is if you have 4 gallons to sparge with, do 2 sparges with 2 gallons each. The idea being that you'll rinse more sugars off the grains that way. I haven't done extensive testing on this, because I implemented a number of changes to my process and my efficiency numbers started getting good so I kept them all.
Practice
When you first start out, there is a lot going on in an AG brew day. After a while, you get comfortable with the process and are able to focus on smaller details and improve your process. I guarantee that if you follow the guidelines in the sticky post and brew 2-3 more batches your efficiency will be up and you'll be happy with your results.
One other note that I want to put in here for completeness is regarding your brewing water. I started looking into the water chemistry side of AG brewing and found that Calcium is a critical mineral needed during the mash. The water reports from my municipal water supply show that my water is very poor in calcium. I have since started supplementing my mash water with CaCl2 to provide the calcium level needed for proper enzyme activity during the mash. Of course, I know I'm probably an outlier here and most people won't need to do this.