Obviously, you don't want your beats to sound out of time, but if your rhythms are too rigid then they run the risk of sounding stale.
What you need, then, is a human touch, and we can tell you how to apply it.
1. It's all about timing (values)
Although it’s a shortcut, you can always test timing values by using your DAW’s track delay to push or pull an entire drum part earlier or later in time - providing its component sounds are split across separate tracks. This can give you an instant indicator of how your groove will respond to particular elements being shifted.
Turn off your quantise grid, duplicate one of your main notes, then place a very short, low-velocity copy of that note just before the main hit, so it leads into it and creates a ‘flam’-style effect. Try this with a run of repeating notes - again, closely positioned and off the grid - for more eccentric fill-style flutters.
3. Shifting parts
Where two drum sounds occur at the same time - snare and hi-hat, for example - try dragging the ‘less important’ element (hi-hat, in this case) ever so slightly earlier or later on the timeline. The main, anchored hit will keep the groove’s timing, but the shifted one will add a natural inconsistency that can sound great in context.
4. Diffuse the situation
A synthetic clap sample will often feature a diffused attack portion, which is designed to emulate several people clapping at once. Push a hit like this earlier in time, just before the beat line, and you can customise its urgency within the groove.
5. Small change
Finally, when applying the tips presented here, try and avoid uniform adjustments on a global scale. It may take you a bit more time, but scour through the groove and make every change different. With practise, you’ll realise how these small changes can massively personalise your drum tracks beyond stock groove templates.