For any conlang project,
the Language Construction Kit resource is the go-to for beginners. And if you want some in-depth examples,
Ardalambion has information on Tolkien's Middle-earth languages.
As for your Dwarvish: it depends how deep you want to go down the wonderful rabbit-hole of linguistics. For just "color" or "flavor" a simple cipher of English words will work well enough, and what you have for a script is fine; but if you want something more interesting (and more fun to create) I can provide some guidance. [Note: I am not a linguist by trade, but I have pursued it as a hobby for several years.]
From your document, I'd say you're jumping into this from the wrong side: focusing on the alphabet/writing system rather than the language itself. I echo Parsley's sentiments, and not just because the writing is messy, but because there appears to be no sequence or logic to the glyphs or the sounds they represent. Also the translation is unhelpful, because I don't know what meaning each sound corresponds to.
I'd start by identifying the sounds, or "phonemes," that you want your language to have. If you aren't already familiar with it, then a study of the
International Phonetic Alphabet is in order. It will help you understand how sounds are formed and relate to each other; and, since it's a standardized alphabet, it will make it much easier to describe your work to other people, as they'll be instantly able to understand what you're talking about (e.g. I can't tell from your chart what "zh" stands for--a /ʒ/, as I'd expect, or just a /z/?)
For a "harsh and guttural" sound I'd use mainly stop/plosive consonants (like /p/, /t/, /g/, etc.) and velar/laryngeal consonants (/k/, /g/, /h/, /ŋ/ and so on), supplemented by bilabials (/p/, /f/ (sort of), /m/) and nasals (/m/, /n/, /ŋ/), and with as few alveolars (/t/, /n/, /s/) and approximants (/r/, /l/, /w/, /j/) as possible. The first tend to sound harsher (at least to English speakers) while the last sound clearer and smoother. Note that you can have as many sounds as you want, but in any given sentence stops and velars should dominate. Affricates, like /ʧ/ (English "sh") or /ʤ/ ("j") are also good, because they've got consonants in them. For vowels I'd tend toward extremes--very open (like /a/ ~ /ɑ/), very front/close (like /i/ or /y/) and very back/close (/u/ or /ɯ/).
Once you've got a basic set of sounds, you want words. As I said, you can just cipher from an English dictionary if you like, but that will almost necessitate replicating English grammar--the concept of a "word" is a fraught one, and not all languages see them the same way. Instead you may want to think of them as "roots": basic units of meaning without reference to "part of speech". Point is, associate some group or sequence of phonemes with a particular meaning. To keep with a harsh-sounding language, I'd use lots of consonants and consonant clusters with fewer vowels--you may even want to use some
syllabic consonants.
Once you're happy with your words/roots, now comes the grammar. Again, you can use English grammar as a basis, but the possibilities here are really endless. If you're familiar with any other languages (especially non-Indo-European languages) you can appreciate how diverse grammars can be; and in any case a lot of linguistic research on syntax and morphology will help you to understand a lot more about how language "works," and thus to create a language that feels and sounds more real and alive.
And only after you've done all that, create the writing system. And there's more than just alphabets: there's also
abudigas,
abjads,
syllabaries,
logograms, etc.
Sorry if this is all too much information; I can go through it piece by piece if you have questions (although the Kit linked above probably will answer you better than I can). Alternatively, sorry if you know all this already--I don't know how much you know, so I just tried to give a basic run-through.