I recently purchased a local taco spice blend (basically: chili pepper, paprika, garlic, cumin and oregano) but it tastes bland when I cook with it. In fact, I often find this when I try to use spice rubs (even mixing things from my spice cabinet) on meat. What is the right technique to maximize flavor? For example, I will take my chicken breasts, coat it in the spice mix, and add a little bit of oil and salt. From there, I'll cook in the pan. Food comes out under-seasoned, and I don't really get any of the flavors/aromas that I'd expect. When I use store-bought seasoning, like this one, I always get a better result: good flavors, good "stickiness" to the food. Or, when I use a glaze (eg, a char siu sauce) then I'm able to get great stickiness, coating, and flavor. Is there a trick to getting home made blends and seasonings to "work" on meat? Seems like just mixing and sprinkling on are not sufficient! 
Salt TL;DR, The ingredients you list in your local spice blend doesn't include anything that would primarily hit the salty, sweet, sour, bitter, or umami tastes. The commercial product you link to has ingredients that hit four of those five tastes. Primarily, you probably need to use a bunch more salt, and maybe a touch of something sweet, sour (acidic), and/or umami. In nearly all cases, commercial products taste better because they are heavily salted--but depending on your personal taste & palate, you might also be missing some of the "background" flavors brought by other ingredients.  The product you identified as consistently giving good results has this ingredient list (Ingredients are listed in order by the amount of each item--that's important to remember):  Yellow Corn Flour, Salt, Maltodextrin, Paprika, Spices, Modified Corn Starch, Sugar, Citric Acid, Yeast Extract, Natural Flavors, Silicon Dioxide.  You can look at this ingredient list to get a better idea of differences between what you might be putting together at home, compared to this product that you know you like. Hopefully, by looking closely at the one you do like, it will help you identify what you're missing (and why) from the other mixes that fall short. Yellow Corn Flour You'll notice the first ingredient is corn flour (corn starch is also listed separately further down). In the context of taco seasoning, this is a binder & thickener for the "sauce" that coats the meat. But you'll often see starches & flours used as a sort of binding "glue" to help seasoning stick to the (wet) surface of food. Salt The second ingredient is salt. This means that there is more salt than any other spice or seasoning. Salt is a fairly critical ingredient to make food taste like itself. This is why "a pinch of salt" is so ubiquitous in recipes, even for non-savory things. If you're finding that you use a bunch of spices, and it still tastes bland, my first guess is always that you didn't use enough salt. There are some alternative methods, but when comparing homemade spice blends to commercial spice blends, it is almost guaranteed that a major taste difference is that commercial spice blends have a lot of salt. Maltodextrin Maltodextrin is another bland-tasting ingredient that serves as a binder or thickener, rather than a flavoring. Paprika, Spices Finally, the 4th & 5th ingredients represent the actual "spices" that make up this taco seasoning. These two ingredients alone represent the entire list of ingredients you noted on your local taco seasoning mix (chili pepper, paprika, garlic, cumin and oregano). Modified Corn Starch More binding/thickening. Sugar Sweet is another "base" taste, where a little bit of sweet can make other flavors "pop". This is another spot where adding just a little sugar to homemade spice blends can help them taste more like commercial products you love. Additionally, it seems that Americans love sweet things, so this pops ups in most commercially available products in US groceries, especially seasonings & condiments. Sugar can also help with browning, and as it melts (around 367°F), it will get sticky. Citric Acid Salt, sweet, and acid (which is sour) are three of the main "base" flavors, and this item in the ingredient list brings the third one into the packet. Having all three in the right proportion can help food taste well-balanced or "well-rounded". At home, a squeeze of citrus juice, or splash of vinegar can replace citric acid in commercial products. Yeast Extract This bring umami to the party. Umami is another "base" flavor, which is usually described as "savoryness" or sometimes "meatiness" (many sources of umami are not meat, so while I don't love that description, many people find it helpful). Yeast extract has glutamates, which are the food science word for the compounds that taste umami (like the way sugars taste sweet). Another popular glutamate is monosodium glutamate (MSG), but many manufacturers shy away from including MSG on the label because of it's (IMHO unfounded) reputation. You can get yeast extract or MSG for your home spice cupboard if you're missing that background hit of umami from this. Natural Flavors There's a long list of things that this could be, but most likely they are just very small quantities of things that are tasty. Silicon Dioxide This is another utilitarian ingredient, rather than a flavorful one. It is an "anti-caking agent," which just means that it keeps your spice blend from clumping together. Spice blends that don't contain anti-caking agents tend to stick together, and you get one big lump, particularly when the air is humid. 