If the cable works, you're probably good.
The cable itself (we're talking copper, not glass here) is pretty foolproof -- hard to damage and unlikely to pick up interference from poor placement unless you do something really stupid.
The hard part is the connections. You do, of course, have to get the wire colors right, and you need to get all the wires connected (sometimes you may not have a wire pushed all the way into a RJ45 plug, eg, prior to crimping). Having the cable "work" gives you a good bit of confidence, but sometimes you can have wires crossed and some adapters will, well, "adapt", whereas others will choke on the bad wiring. Plus you may have currently unused wires improperly connected and they will fail if you ever use the unused wires (though ever using more than 4 of the 8 wires is unlikely outside of PoE, and many PoE schemes don't use more than 4).
But if you leave enough slack on both ends then you can always re-terminate a poorly terminated cable.
But note that you can purchase a simple RJ45 cable continuity tester fairly cheaply. These don't test for frequency response and cross-talk, but they check that the connections are correct end-to-end.
[I'll add that one likely novice mistake is to quickly glance at the color code chart and make the improper assumption that the RJ45 is wired pair/pair/pair/pair. In fact, there are pairs on each end, a pair in the middle, and then the last pair is split and "straddles" the middle pair.
Another novice mistake is to get confused by the several different color code "standards". There are three or four different ones, that put different colors on different pins. It really doesn't matter which standard you use, so long as you use the SAME STANDARD ON BOTH ENDS.
And it DOES matter that pairs are kept together -- where there is supposed to be a "pair", you should not use one wire from one pair and another wire from a different pair. While the cable may "check out" on the cheapie cable tester, there will be crosstalk and poor performance/high error rates in practice.]