one area that seems to cause problems in all wiring systems, from simple 8 circuit kits to the complex systems used in OEM vehicles of today, are the terminations at the various plug-ins. this is caused by several things, ranging from using cheap terminals, using the wrong tool for the crimp, or not crimping the terminal correctly.
if a person is not familiar with how to terminate wire ends, Utube is your friend.
and it goes without saying, stay away from those 673 piece terminal kits with the crimper for only $1.32 from elchipistan fright. way better terminals, as well as reasonable quality crimpers can be had from places such as dell city for not much more money.
make sure the kit you purchase has the correct gage wire for the load it has to carry. the charging and starting circuits better have much larger gage wire than the tail light circuit. i have run into, over the years, a couple "bargain" kits that had way undersize wire on all circuits. that is just asking for trouble.
finally, purchase some extra terminals and wire of various sizes to practice on making correct termination crimps with the tool[s] you decide to use. it's a little extra money, but well spent, especially if you have seldom [or never] done this work. it will pay off in the long run.
every new wiring tool i buy [and i have a BUNCH of 'em] i practice with before i tackle a job. this allows me to get a feel for the tool, as well as view how good of a job it will do.
take your time and plan out the route of the circuits, mount the kit components carefully, and you will be happy in the end with a job well done !