You can do it! Just determine what you are going to make and then sit down and do it.
People at the shop are all the time marveling how fast I get things done, so here are a few tips that help me.
Determine your pattern and stick to it, no changing it up as you go
Don't stop to admire work just done, keep on working
Set a timer for 30 minutes, get up and walk around the house every time it goes off so you won't get stiff
Wind all your bobbins at one time - or as many as you can
Don't dither, just go with the plan
Don't start counting how many done and how many to go, it will not make a difference in how to sew what you have in your hand