I'm late to this thread, but here some techniques that I learned that could possibly help you out.
1) When you sample, try to sequence other parts on top of your main chops, for example this can be some vocals from the original sample or a minor chop, throw a high pass fitler on it (cut out the low frequencies to remove bass, but make it extreme high pass, remove like 1000hz of low pass, [the entire left half in Paramatic EQ2]. This will remove the bass and low end, you throw that on top of your main chops, and you good money, it will make your sequence stand out more, and it will help make the beat sound less repetitive, you can use that for a chorus or half of a verse.
This is an example of what I mean, we took a main sample and had it loop for the whole beat, but threw on there some minor chops and vocals from the main song we sampled from:
2) Another technique which is useful is to sample from drum breaks and drum loops. This technique has been used by the old heads since the beginning of hip hop. It's a technique that is kinda dying down, but is very useful to make your beats sound complete.
This is an example of that [this example also has the technique I mentioned above with the sample chops]:
Another example using technique 1:
Also as you keep practicing, don't just loop over the same drum patterns. You should make different unique patterns, such as a beat drop or a mute for the end of a verse or chorus. [Removing the kick and snare for the 1/4 of a bar]
Also experiment with having multiple drum patterns, 1 pattern can be a set kick, snare, and hi hats for 8 bars, while the next pattern has different steps on the pattern. Also experiment with adding in drum fills and tom rolls. More percussions, things like that. These may seem like little things, but trust me it really makes a difference.
Also experiment with playing with different effects on your samples, try adding a little reverb, a 1/4 delay, and EQ your sample. Doing this makes the sample sound fuller, especially when there is a little pause or minor mute during your chop sequences.
Another thing I recommend is, when you get more practice, try to make melodies that match your sample, this will make your sample sound even more complete. By doing this you can even have a part of the beat where you don't need to play the sample. This technique works well when making your own bassline for the beat.
If you don't know how to make a bassline yet matching your sample, one technique I've used in the past was to make a duplicate of my sample track, and on the duplicate, take off the high end (remove everything past 350hz) this makes the sample play as if it was a bassline.