Mexico works hard to protect its citizen workers and they make it not so easy to work as an expat, but it is certainly possible.
If you don't have a residente permanente, you will need to get the work permit add-on for your residente temporal, which you generally need to show a degree in your field to receive. I don't believe that is a legal rule but that is what I was asked for. If you don't have a degree, it may be tougher.
Without Spanish skills you are looking mostly at either timeshare sales or call center work. Tourism work might be possible but you will have stiff competition from English speaking natives, of which there are many. Wages are very low compared to what you are used to. Minimum wage is less than $5 PER 8 HOUR DAY, not per hour!
Do you do graphic arts work? You could work via internet for US based clients and make a lot more.
Working in Mexico isn't easy nor a given.