We've singled out Shelter Systems Grip Clips because they are just a great solution to adding guys to virtually any tarp without sewing or damage.
Shelter Systems says:
The Grip Clip tarp and fabric fastener attaches quickly and easily to a tarp or any fabric without tools. It can be used to join two tarps or to shape a tarp to fit a desired function by gathering up a fold. It also provides a secure anchor for staking or attaching poles or guy lines. You will find endless uses for them at home in the garden at construction sites and while camping boating snowmobiling hunting fishing and more.
The Grip Clip tarp fastener is specially designed to lock on to tarps and fabrics without puncturing them. The GP and HD Grip Clip tarp fastener will withstand a 150-to-200 lb. pull without coming off or tearing the tarp at the point of attachment. We achieve this through the following design features. The tarp passes over and under multiple sections of the tarp fastener. Thus the tarp is in contact with a large surface area of the fastener. By spreading out the force exerted on the tarp and increasing the friction between it and the fastener the tarp is prevented from slipping or tearing. The two pieces of the Grip Clip tarp fastener lock together (somewhat like a button in a button hole) engaging the tarp between them so that the two pieces cannot come apart accidentally.
Construction - The Grip Clip tarp and fabric fastener is made of a UV-stabilized (for longer sun resistance) extremely tough and durable co-polymer. The tarp fastener`s trademark color is white to reflect the sun`s heat and light which will prevent the sun from degrading the tarp at points of attachment. The cord provided with each Grip Clip is a super nylon with high weight-bearing strength.
Revolution - The Grip Clip tarp and fabric fastener will revolutionize the way you think of tarps. No more grommets ripping out and your expensive tarp ruined flapping in the wind. You will find that you can--on the spot--join and shape tarps to create watertight covers without resorting to sewing (time consuming and leaks at the seams) tape (messy and peels off) or other tarp fasteners (which pop off).
One of those brilliant yet simple devices that really work. Counter intuitively the smaller Micro Grip Clips are more expensive of the two because they are more difficult to manufacture.
Two part 'button' fastening