It's not our job to tell you which parts need to be changed in order to make the front look good, a few people have said similar things about the front - that it doesn't showcase good graphic design skills, and in my experience, when people say this there is often so much wrong with it it's difficult to know where to start. It usually means going back to the drawing board for the designer, and doing some research into what constitutes good design. Get some magazines, pick apart the reasons some things look better than others, get a really good understanding of how things relate to each other on the page, how typography can make a huge difference to a design, how colour has an emotional impact and how visually something guides your eye around the page.
However, I will start with just a few pointers to get the ball rolling:
Embroidery service - the gap between the two words is huge
I think you have gone for one of those DIY kit looks for the front where you pop off the bits too assemble something, but I'm not sure of the connection to design services?
The fonts used need some work, at the moment I can't decide whether there are too many different ones going on or not enough, I'd try out some other options
The images of the van and the t-shirt look like they came straight off a stock image site - even if they did, make them more your own
The colour scheme does not look well considered, it looks like default swatches that haven't been tinkered with in any way to make the design stand out.
If you are to stick with the DIY toy kit idea I think the parts which are meant to be the plastic connections need to be more obvious what they are. When you look at these kits they are usually all one colour, perhaps limit your colour pallet and see what this does to help your design shine through. The 'pieces' would also need to look more like the pieces of the toy. It needs consistency.
Hope this helps, I know it can be a little frustrating when people come back with criticism to a design with not much more than "needs more work" or "doesn't look right" but often we can see that something doesn't look right and we need time to investigate exactly why.