How to get good graphics on terrain

I have a terrain with a texture I downloaded off the internet, along with some hills and mountains. My problem is that the hills and mountains do not very good graphics such as: blurry texture, some jagged edges, and etc. The scene takes place on mars, and does not have very good lighting ( the only lighting being the flash light and a .1 intensity orange directional light). Also, the texture does not have a normal or mask map if that matters. All I want are some better graphics. If you can help, it would be GREATLY appreciated.

The problem is with the assets it seems.

Honestly (this is not a marketing plug!), check out Substance Suite for creating your own textures (free for students, otherwise $20/month or so). If you google image search, for modern rendering you can’t realistically just stick a .jpeg in and expect it to be ok. You need metallic/smoothness (mask) and normal maps at the least; normal map online (google it) can make normal maps for you in a pinch but you probably need better base textures. In particular they need to tile, and be square (256x256, 512x512 etc.).

It is unfortunately very hard to make modern textures that look ‘ok’ without Substance, or a huge timesink. They have pretty much cornered the market on this.

If substance is a no-go, in free solution terms:

Use it’s filter to make the texture seamless
Create a 2nd texture (mask map) that has red pixels where stuff is more metallic, and alpha=1 pixels where stuff is smoother (more reflective/specularr)
DL GIMP normal map plugin or use normal map online for a crude normal map based on height
Export the 3 files and use them.

The other obvious solution is just to d/l or buy a texture that has all 3 maps. I would honestly recommend Substance as an amazing set of tools that makes texturing go from ‘I can’t do it’ to ‘omg what I made looks so awesome’.