Doesn't look bad at all bub but I have a few suggestions.
1) Center the lettering across the top and maybe add some depth through outlines or shadows.
2) The flag on the side should always look like it is charging not flowing backwards (retreating).
3) Look at adding little details, stickers and little things always make a big difference in the finished product.
4) The goal should always be a good flow from front to back, you have a great start here but don't be satisfied with just this, look at it like a real truck and find the flow.
I will be looking for more of your work in the future, you have alot of potential. Never give up bub and keep working.
Also if you DM me I will send you some better rear chevrons that have a pseudo-reflective look.